The C. Chen Collection: “Kogkhulion”

“Kogkhulion” (Greek: “Conch”) is a photographic reference to world molluscs using specimens from the C. Chen Collection; continually updated. Mouse-hover over an image will display the scientific name, clicking/tapping reveals the full image with a detailed species account. For a searchable version, click here.

Pionoconus gauguini (Richard & Salvat, 1973)<br />
CONIDAE<br />
Marquesas, French Polynesia, 2012/x, 70.4mm <br />
<br />
With a very limited distribution range from Marquesas Islands to Tahiti and Society Islands, the "Gauguin's Cone" is one of many stunning conids endemic to the French Polynesia. An uncommon to rare species, it is much coveted by shell collectors and command high prices in the shell trade. A carnivorous and predatory gastropod that actively hunts polychaete worms, it inhabits sand to rubble bottoms of coral reefs around -15~40m deep. It is nocturnal and spends daytime buried in sand under slabs of rocks or coral. The colouration varies from light pink to dark purple, brown to black blotches of various sizes are sometimes present. Typical shell length around 65mm, extremely large specimens may exceed 90mm. It is conchologically very similar to Pionoconus barthelemyi from western to central Indian Ocean, despite the great distances separating the two. Compared to P. barthelemyi, P. gauguini has a smoother shell surface and a more sharply carinate shoulder. Furthermore, the surface colouration of P. barthelemyi is generally orange to red whereas it is pink to violet in P. gauguini.

Here's a "shell" which deceives.... :)<br />
<br />
Stylobates aeneus Dall, 1903 <br />
ACTINIIDAE<br />
-600m (-2000ft.), From shrimp traps, Off northern Oahu Island, Hawaii, USA, 2003/iii, 56.7mm <br />
<br />
Superficially, the "shell" of Stylobates aeneus looks exactly like a gastropod shell, complete with an umbilicus. Quite understandably, it was initially described by Dall as a trochid. It is however not produced by a mollusc at all -- instead it is the work of a rather rare shell-forming actiniid sea anemone (Cnidaria: Anthozoa) capable of secreting a proteinaceous "shell" made of chitin, termed "carcinoecium" (i.e., "house of crustacean"). After examining further specimens, Dall realised his mistake and published a short note in 1919 to correct his erroneous phylum placement. A deep-water anthozoan, it inhabits sandy bottoms around -400~800m deep and lives obligately in association with hermit crab hosts, the host species being Sympagurus dofleini (Balss, 1912). This is considered to be a case of mutually beneficial symbiosis: by living on the back of hermit crabs, Stylobates gains a means of transportation as well as food scraps from the hermit crab; while the hermit crab gains protection from predators by the sea anemone's nematocysts (stinging cells). Members of the genus Stylobates (four described so far) are the only sea anemone known to have the capability of producing entire "shells" for their hermit crab hosts, although some others are known to extend the existing shell slightly. Still, Stylobates must first settle on an existing gastropod shell, from where it starts the shell making process. Therefore at the apex of the carcinoecium a true gastropod shell can always be found. Being able to make a shell for the host means the hermit crab no longer needs to find replacement shells as it grows, thus forming life-long relationships with the sea anemone. Stylobates aeneus was originally described from Hawaii but its distribution is now known to reach Guam. Specimens collected in Japan are generally also referred to S. aeneus and share the same host species, Sympagurus dofleini, but these differ in some aspects of the morphology and may represent a different species. Typical width of the carcoenecium is around 50mm, very large specimens may reach 80mm. Fresh carcinoecia are gold to bronze in colouration but over time those preserved dry often darkens and conversely specimens fixed in alcohol may lighten. The carcinoecium is very thin and fragile as it does not possess a calcium carbonate layer, to the extent that it often collapses when the host hermit crab is removed. Intact specimens of the carcinoecia are therefore rarely seen.

Mirapecten cranmerorum (Waller, 1986) <br />
PECTINIDAE<br />
-150~200m, Trawled, Off Somalia, 2008/x, 71.2mm <br />
<br />
Mirapecten cranmerorum is a gorgeous pectinid endemic to waters off eastern Somalia. A greatly coveted rarity and collector's item, much of its apparent scarcity now is due to its limited distribution in the Somali waters where piracy is a real threat. Once ago it was only uncommon and much less costly to obtain, when occasional supplies brought considerable numbers to Europe. Sparse scales are present only on the left valve, which is usually darker coloured and slightly more convex compared to the right valve. The colouration varies slightly from orange to red and the patterning differs among individual specimens. A filter-feeding bivalve, it inhabits hard bottoms on moderately deep waters around -80~200m. Typical shell length around 60mm, very large specimens may exceed 80mm. A new genus, Somalipecten, was proposed for it as part of the original description but this is now considered to be a junior synonym of Mirapecten.

Neocancilla takiisaoi (Kuroda, 1959) <br />
MITRIDAE<br />
-20~30m, Dived, Zampa-misaki (Bolo Point), Okinawa Island, Japan, 2002/x, 50.0mm <br />
<br />
With a wonderful combination of triangular 'tent' pattern and cancellate sculpture, the unmistakable "Isao Taki Mitre" is one of the most exquisite mitrids in the world. Widely distributed in the Western Pacific ranging from Japan to New Zealand to as far east as Pitcairn Islands, its type locality is Hachijō-jima, Japan and most specimens appear to originate from either southern Japan or New Caledonia. Its beauty and the fact that it is a very scarce species makes it one of the most desired mitres of all, made famous by featuring in "World Seashells of Rarity and Beauty" (1991) depicting a shell from the R. Kawamura collection, as well as T.C. Lan's "The Classic Shells of the World" (1993). It is sometimes beached, albeit very rarely and usually in poor condition. A carnivorous and predatory gastropod presumably feeding on sipunculid worms, it inhabits sand or rubble bottoms of moderate depths around -20~100m. Typical shell length around 45mm, extremely large specimens may reach 65mm. It is named in honour of Dr. Isao Taki (1898-1961) who was an influencial malacologist and zoologist in Japan, along with his younger brother Dr. Iwao Taki (1901-1984).

Zoila jeaniana (Cate, 1968) <br />
CYPRAEIDAE<br />
-20~40m, On sponge, Dived, Shark Bay, Western Australia, Australia, 2005/i, 64.3mm <br />
<br />
The "Jean's Cowrie" is a delightfully patterned cypraeid endemic to Western Australia, Australia; ranging between the Montebello Islands in the north and around Kalbarri in the south. It can be differentiated with other similar Zoila species by the presence of columellar dentition and a base with uniform orange to brown colouration, bounded by a pale margin. Like almost all Zoila species, it has been divided into many forms/subspecies. The nominal form is moderately rare and usually trawled from around -80~150m deep, occasionally found as shallow as -40m. The form sherylae Raybaudi, 1990 (shown here) from Shark Bay area is only uncommon due to its shallower depth around -20~60m, and is generally smaller than the nominal form. The rare form thalamega (Lorenz, 2002) consists the southmost population around Kalbarri; it inhabits shallower depths around -20~80m and is characterised by more elongate shell with rostrate tips. The name aurata Raybaudi, 1979 refers to rare deep-water shells trawled from -150~250m around northern Western Australia, characterised by much paler and typically golden colouration. It used to be treated as a valid subspecies but genetic examination in the recent years could not differentiate it from the nominate subspecies; it is currently treated as taxon inquirendum but in reality is probably merely a deep-water variation and not worthy of a subspecific rank. It is a carnivorous grazer feeding solely on demosponges, as is typical for Zoila. Typical shell length around 75mm, very large specimens may reach 110mm. It is named after Mrs. Jean Cate, wife of the Cypraeoidea specialist Crawford N. Cate who desribed this species.

Janthina janthina (Linnaeus, 1758) <br />
JANTHINIDAE<br />
Beached, Dampier, Western Australia, Australia, 2003/i, 33.0mm <br />
<br />
The "Common Violet Snail" is a gorgeously coloured janthinid with an extremely wide distribution across the world's warm and temperate seas due to their wholly pelagic lifestyle. The foot is specialised in making air rafts from mucus which enables it to float the on sea surface, usually apex-down. The splendid colouration is thought to be a camouflage to match the colouration of surrounding seawater. Furthermore, its shell is lighter coloured above the suture, considered as an example of counter-shading to make it blend in to seawater and difficult to find for predators when seen from below. It is a hermaphrodite exhibiting protandrous hermaphroditism, meaning each individual begin life as a male and then changes sex to female at a later stage; thus small individuals are males and large individuals are females. A predatory snail feeding on pelagic jellyfish encountered on the sea surface, two common preys include the pelagic hydrozoans "By-the-wind Sailor" Velella velella (Linnaeus, 1758) and "Portuguese Man O' War" Physalia physalis (Linnaeus, 1758). It is common and often occurs in large aggregations of dozens of individuals. In events of strong winds or storms whole aggregations are frequently stranded and beached; such events are greatly prized by beachcombers as it is otherwise only rarely beached. Typical shell width around 30mm, extremely large specimens may grow to 45mm.

Mitra hayashii (Kira, 1959) <br />
MITRIDAE<br />
Off Saga, Saga Prefecture, Japan, 1990/vi, 54.0mm <br />
<br />
The "Hayashi's Mitre" is a famous and much sought-after Western Pacific mitrid ranging from Japan to the Philippines. When initially discovered in Japan, it was thought to represent a recently extinct species as no live specimen was found. Many years later however, live specimens started to surface. In fact it is named after Mr. Shoichiro Hayashi, the first person to collect a fully mature specimen of this species alive and provided it for description. It used to be rare to very rare, and was made famous by inclusion in the classic book "Rare Shells of Taiwan" (1979) by T.C. Lan. Majority of specimens do actually come from Taiwan, although recently more specimens are surfacing from the Philippines. It has become more readily available in the recent years and is now perhaps best described as uncommon or moderately rare. A carnivorous and predatory gastropod feeding probably on sipunculids like most mitrids, it lives on soft bottoms of rather deep water around -100~300m. Typical shell length around 50mm, very large specimens may exceed 65mm. Though used to be placed in the genus Scabricola it is now generally accepted to be a member of Mitra and included in the subgenus Nebularia, considered by some to merit a full genus status.

Ficus investigatoris (Smith, 1894) <br />
FICIDAE<br />
-150~200m, In fisherman's net, Muttom, Kanyakumari District, Tamil Nadu, India, 2015/x, 130.0mm <br />
<br />
The "Bengal Fig" is a large and intricately sculptured ficid found exclusively in the Indian Ocean, ranging from Bay of Bengal to Mozambique; the type locality being "Off Ganjam coast, eastern India". For many years it was considered a rare shell as the main supply was by-catch from trawlers working off Somalia, but very recently fresh supplies have emerged from India and it has become much easier to obtain. In its natural habitat it is a locally common gastropod mostly seen on sandy to muddy bottoms of rather deep water around -100~400m, although occasionally it is found as shallow as -30m. Ficidae is considered to feed by swallowing small organisms with detritus and organic particles, though some claim they feed on echinoderms and polychaete remains have been detected in the digestive tracts of Ficus. The surface sculpture is characteristic and little-varied among individuals, although the shell width to height ratio varies considerably. Typical shell length around 100mm, very large specimens (as shown) are known to exceed 130mm. In "A Conchological Iconography: The family Ficidae" (2000), Varhaeghe & Poppe cited the authority of this species as "Smith, 1906", but this was due to a confusion between two references by the same author and it was actually described in 1894. The specific epithet refers to the H.M. Indian Marine Survey Steamer "Investigator" which collected the first specimens that became the basis of the original description.

Barnea dilatata (Souleyet, 1843) <br />
PHOLADIDAE<br />
-20~30m, Trawled in mud, West Phuket Island, Thailand, 1998/ii, 79.3mm <br />
<br />
The "Dilate Piddock" is a large burrowing pholadid with a rather wide distribution in the Indo-West Pacific, ranging from Japan to India to Australia. A common filter-feeding bivalve with a much larger body than the shell, it lives deeply buried in sand or mud in shallow water from intertidal down to about 20m deep. Its very long siphon (up to four times shell length), which it uses to feed, is considered a delicacy in some places. For example in Ariake Sea, Japan it is a famous local speciality and is widely harvested to be eaten either fresh or dried; although its numbers in that area appears to be diminishing in the recent years. The shell is very fragile and has one calcified accessory plate, the protoplax. The apophysis, spoon-like appendage serving as a point of attachment for the foot musculature, is very long and narrow. Typical shell length around 80mm, very large specimens may exceed 120mm.

Luria tessellata (Swainson, 1822) <br />
CYPRAEIDAE<br />
-5~10m, Dived, Oahu Island, Hawaii, USA, 32.2mm <br />
<br />
The "Checkerboard Cowrie" is a highly distinctive cypraeid with its four characteristic dark blotches on the dorsum. An exceedingly famous and much sought-after species, it is very variable in blotch development and is thus not easy to find a specimen with well-balanced 'checkerboard' pattern; it is also rather variable in callous development. An omnivorous gastropod, it lives under corals and rocks from rather shallow to moderately deep water ranging around -3~50m. Almost all specimens are from Hawaii where it is uncommon (live specimens becoming rarer recently) and it was once thought to be an endemic there. From the 1980s, however, a few have been taken live around Taiwan and more recently in the Philippines; its true range therefore appears to be quite wide. It appear to only occur in the deep water in the western Pacific and is extremely rare there; the name Luria lani (Raybaudi 1986) was given to the Taiwanese population but is currently regarded as a junior synonym. Typical shell length around 30mm, extremely large individuals are known to reach 55mm.

Calliostoma toshiharui Kosuge, 1997 <br />
CALLIOSTOMATIDAE<br />
-150m, By tangle nets, Aliguay Island, Zamboanga Peninsula, Mindanao, Philippines, 2003/viii, 44.4mm <br />
<br />
The "Toshiharu's Top Shell" is a large and spectacularly ornamented Western Pacific calliostomatid ranging from the Philippines to Borneo. It is characterised by two to three spine-bearing spiral cords just above the suture, although the development of spines vary among individuals. The whorls are strongly shouldered due to the spine-bearing cords being especially prominent and thus appear slightly concave. A rare species even in the usual dead collected condition, live taken specimens without significant damage (as shown) are very rare. Most likely a carnivorous grazer feeding on tissue of cnidarians like most calliostomatids, it inhabits rather deep water around -150~300m. Typical shell height around 35mm, extremely large specimens may exceed 50mm.

Tonna melanostoma (Jay, 1839) <br />
TONNIDAE<br />
-60~80m, In fishing net, Off Kakeromajima, Amami Islands, Kagoshima Prefecture, Japan, 2007/vi, 235.9mm <br />
<br />
With a unique dark aperture the "Black-mouthed Tun" is an unmistakable and extremely handsome tonnid ranging from southern Kagoshima Prefecture, Japan to New Zealand. It is not only the most coveted and sought-after tonnid species of all, but also a species of legendary fame and rarity among all shells. A very large tonnid with an average shell length around 220mm, extremely large specimens are known to exceed 300mm. Despite having a large size and being easily recognisable it is very rare across its rather wide range, especially adults displaying well the signature black mouth. Most specimens appear to originate from either southern Japan or around New Caledonia, although recently young specimens have been surfacing frequently from the Chinese coast. Young specimens lack the signature "black mouth" as that only develops as the snail matures, but the characteristic sculpture of alternating thick and thin spiral cords make them unmistakable still. The only species it may be mistaken with is its sister species Tonna hawaiiensis Vos, 2007 which is endemic to Hawaii and has been wrongly treated as the same species for many decades. Tonna hawaiiensis, however, is a much smaller species on average and never develops a fully black aperture to the extent of T. melanostoma even when mature. Like other tonnids it is a carnivorous and predatory gastropod inhabiting sandy to muddy bottoms and predominantly hunts holothurians (sea cucumbers), most likely nocturnally.

Cymbiola irvinae (E. A. Smith, 1909) <br />
VOLUTIDAE<br />
-120m, Trawled on sandy to muddy bottom, South of Mandurah, Western Australia, Australia, 78.3mm <br />
<br />
The "Irvin's Volute" is a solid volutid endemic to the western shoreline of Western Australia, Australia. A little-varied species in terms of patterning and form, but the extent of shoulder spine development is very variable from being completely smooth and spineless to having long and recurved spines. It is a rather rare and sought-after species that is usually dredged dead or crabbed, live-taken specimens are very rare. Although it closely resembles the much more common Cymbiola nivosa (Lamarck, 1804), that species has a much smaller protoconch and less dense shoulder spines (when present) which are always solid and not hollow like those of C. irvinae. A carnivorous and predatory gastropod feeding on other invertebrates, it inhabits sand or gravel bottoms of moderately deep water around -50~250m. Typical shell length around 100mm, extremely large examples are known to reach 130mm.

Perotrochus wareni Anseeuw, Puillandre, Utge & Bouchet, 2015 <br />
PLEUROTOMARIIDAE<br />
-350~450m, Dredged, Grand Passage, North of New Caledonia, 45.4mm <br />
<br />
The "Warén's Slit Shell" is a small pleurotomariid endemic to New Caledonia, characterised by a fine pustulose sculpture. For many years, it was considered to merely represent a 'pustulose form' of P. caledonicus Bouchet & Métivier, 1982 which occured allopatrically and shared with it similar size, colour, and shape. The type specimen of P. caledonicus, however, had smooth and unbeaded spiral cords; no clear intergrades between the two forms were known. Only very recently, a study using both morphological and molecular data finally revealed that the two in fact represent two distinct lineages and are separate species. The 'pustulose form' was therefore described anew, as Perotrochus wareni, shown here. Though the two species appear to occur allopatrically in New Caledonia, P. wareni is more common in the northern New Caledonia while P. caledonicus is predominantly found in the southern areas around Isle of Pines. They also differ slightly in depth preference, with P. wareni occuring mostly around 350m deep and P. caledonicus slightly deeper at around 400m. Furthermore, the range of P. wareni extends westwards to Lansdowne Plateau in the Coral Sea but the range of P. caledonicus does not appear to reach the Coral Sea at all. The population from Chesterfield Plateau in the Coral Sea, previously attributed to P. caledonicus, was revealed to be a further distinct species in the same study and was named P. pseudogranulosus Anseeuw, Puillandre, Utge & Bouchet, 2015. It inhabits hard substrates and is a carnivorous grazing gastropod feeding on demosponges. Typical shell length around 40mm but extremely large specimens may exceed 70mm. Though it is locally somewhat common, high quality specimens are uncommon on the shell trade market.

Perotrochus caledonicus Bouchet & Métivier, 1982 <br />
PLEUROTOMARIIDAE<br />
-350~450m, Dredged, Southwest of the Isle of Pines, New Caledonia, 50.5mm <br />
<br />
The "New Caledonia Slit Shell" is a small, lustrous pleurotomariid endemic to New Caledonia as its name suggests. For many years, this species was thought to occur in two forms with distinct sculpture -- a 'smooth form' with uninterrupted spiral cords and a 'pustulose form' with the cords divided into many conspicuous beads. Although no obvious intergrades were known, the two were similar in size, colouration and shape as well as co-occuring in similar areas and were thus assumed to represent a single species. A recent study using both morphological and molecular data clearly revealed, however, that the two in fact represent two distinct lineages and are separate species. The 'smooth form', as shown here, corresponds to the nominal P. caledonicus and is more common in the southern New Caledonia, though the distribution range does extend northwards up to the Grand Passage area. The 'pustulose form' was newly described as Perotrochus wareni Anseeuw, Puillandre, Utge & Bouchet, 2015; it is more common in the northern New Caledonia but also occurs in the south, and the range extends westwards to Lansdowne Plateau in the Coral Sea. These two species differ slightly in depth preference, with P. caledonicus occuring mostly around 400m deep and P. wareni mostly around 350m deep. The population from Chesterfield Plateau in the Coral Sea, previously also attributed to P. caledonicus, was revealed to be a further distinct species and was named P. pseudogranulosus Anseeuw, Puillandre, Utge & Bouchet, 2015. The name P. caledonicus therefore currently refers solely to the 'smooth form'. A carnivorous grazing gastropod, it lives on hard substrates and feeds on demosponges. Typical shell length around 40mm, extremely large specimens are known to exceed 65mm. Though it is locally not uncommon, high quality specimens are still uncommon in the international shell trade.

Bursa verrucosa (Sowerby I, 1825) <br />
BURSIDAE<br />
-25m, SCUBA dived, Raoul Island (Sunday Island), Kermadec Islands, New Zealand, 31.6mm <br />
<br />
With numerous black warts well-contrasted against a whitish-yellow background, the "Verrucose Frog Shell" is one of the most striking bursids of all. The shell form is little-varied, but the warts vary in strength among individuals, in many cases a series of warts are reduced to a simple 'dotted-line'. It has a much restricted distribution from southeast Australia to Lord Howe Island, Norfolk Islands, Kermadec Islands, and northern New Zealand. One of the rarest frog shells and specimens are much sought-after by collectors, especially those with large and well-formed warts. It inhabits sandy to muddy bottoms of shallow subtidal water around -10~40m deep, and is a carnivorous gastropod like other bursids, probably mainly feeding on polychaete worms. Typical shell length around 30mm, very large specimens may exceed 55mm. A monotypic genus Annaperenna Iredale, 1936 was once proposed for it, but is now regarded as a synonym of Bursa.

Mikadotrochus salmianus (Rolle, 1899) <br />
PLEUROTOMARIIDAE<br />
-250~300m, Trawled, Off Kashiwa Island, Kōchi Prefecture, Japan, 1983/v, 93.5mm <br />
<br />
The "Salmiana Slit Shell" is an elegant pleurotomariid with a blazing coluration and a characteristically tall spire, ranging from Honshu, Japan to Taiwan to Philippines. A much sought-after rarity, most specimens have generally come from Taiwan although recently Chinese fishermen have also trawled many (mostly poor) specimens from the East China Sea. It reaches the largest size in Tosa Bay, Japan where the shells are the thickest and with a rather pale colouration; the shells gradually thins down towards south with specimens from the Philippines being the lightest in build but with a dark colouration. Both Tosa Bay and Philippines specimens are still very scarce today, especially in large size, though in the East China Sea it is probably best described as uncommon. A carnivorous grazer feeding on sponges, it inhabits hard substrates of rather deep water around -100~400m. Typical shell length around 90mm, extremely large specimens are known to exceed 135mm. For many decades since its description it was confused with its congener Mikadotrochus beyrichii (Hilgendorf, 1877) due to the small quantity and poor quality of available specimens. As better specimens surfaced, however, its obvious differences with M. beyrichii quicky became apparent and it has become widely accepted as a valid species since the 1970s. A well-known synonym is Mikadotrochus schmalzi Shikama, 1961.

Tenagodus obtusus (Schumacher, 1817) <br />
SILIQUARIIDAE<br />
Almeria, Andalusia, Spain, 118.9mm <br />
<br />
Tenagodus obtusus is a curiously shaped slit-worm shell with the first few whorls coiled regularly but suddenly shifting to growing an uncoiled tube. It is mainly known from the Mediterranean Sea with specimens from Atlantic waters generally attributed to T. senegalensis (G. B. Sowerby II, 1876), although some authors claim that the two should be considered synonymous. Tenagodus senegalensis appear to have generally more tightly coiled earlier whorls, although they are quite variable indeed. It is an obligatory sponge commensal and spends the entire life inside the host sponge, in most cases Holoxea furtiva Topsent, 1892. More than one specimens is usually found together in a cluster within the sponge. Most of the shell is completely embedded in the sponge which provides shelter and protection, only the uncoiled tube extends out. It is found in intertidal and shallow subtidal waters down to about -50m, and is a filter feeding gastropod. There is a corneous operculum supported by a much reduced foot, which is heavily sculptured with opercular bristles, the form of which is an important taxonomic character in this family. It is very similar in general appearance to the Indo-West Pacific species T. ponderosus Mörch, 1861, but is usually readily distinguishable by the slit morphology -- the slit of T. ponderosus is a series of elliptical holes on the coiled whorls then gradually becoming denticulated and then finally smooth-sided at the uncoiled part, whereas that of T. obtusus is smooth-sided without denticulation throughout the entire teleoconch. Typical shell length around 100mm, extremely large specimens may exceed 160mm. Although generally a common species, it is uncommon to find one in good condition on the shell trade market.

Aplustrum amplustre (Linnaeus, 1758)<br />
APLUSTRIDAE<br />
Dived, Nuku Hiva, Marquesas Islands, French Polynesia, 19.9mm <br />
<br />
The "Royal Paper Bubble" is a most lovely aplustrid shell-bearing opisthobranch widely distributed across the tropical Indo-West Pacific. A carnivorous and predatory gastropod mainly feeding on polychaete worms, it inhabits fine sandy bottoms of shallow waters less than 15m depth and is common throughout most of its range. Generally instantly recognisable by its two characteristic broad pink bands bordered by black lines, but the pattern is actually somewhat variable, especially the thickness of black lines. Specimens from the Marquesas Islands (shown) appear to differ from all other by having much darker colouration and much thicker black lines. Typical shell length around 15mm, extremely large specimens may exceed 25mm. On a side note -- Voskuil (1995) separated from this species Aplustrum exquisitum (Voskuil, 1995) which has one thick black band, instead of two black lines and a white band, between the two pink bands; and tip of the columellar being bent slightly towards the right instead of left when viewed at the aperture view with apex pointed upwards. Aplustrum exquisitum is supposed to be endemic to Marquesas and co-exist with A. amplustre there. However, when one views sufficient material, it appears that A. exquisitum is most likely merely a form of A. amplustre with an uncommon pattern, as a whole range of intermediates can be found in Marquesas.

Buccinum viridum Dall, 1889<br />
BUCCINIDAE<br />
-800m, Trawled, Off Astoria, Oregon, U.S.A., 43.5mm <br />
<br />
The "Turban Whelk" is a deep-water buccinid native to the northern Pacific, best known from the West coast of North America. Although generally an inhabitant of sandy to muddy bottoms of deep water around -700~2500m, it is also an important member of chemosynthetic ecosystems off off California and Oregon, USA, being commonly found in hydrothermal vents (e.g., Explorer Ridge), methane seeps, and on whale falls. It is a carnivorous gastropod but also scavenges when the opportunity arises. There are two forms, one with an obvious spiral cord on the shoulder and the other with a rounded shoulder. Though supposedly a common species, it is quite an uncommon species in the shell trade. It is the type species of subgenus Viridibuccinum. Typical shell length around 40mm, very large specimens may exceed 60mm. A similar species, Buccinum thermophilum Harasewych & Kantor, 2002 is known from the Endeavour Vent Field, Juan de Fuca Ridge, and differs from B. viridum by smaller, narrower, more higher spired shell and a much more ovate aperture. Furthermore, the spiral ridges in B. thermophilum is generally much sparser.

Provocator mirabilis (Finlay, 1926) <br />
VOLUTIDAE<br />
Dredged from deep water, New Zealand, 122.4mm <br />
<br />
The "Astonishing Volute" or the "Golden Volute" is an elegant deep water volute endemic to sub-Antarctic Pacific waters around New Zealand. It is a locally not uncommon predatory gastropod living on muddy bottoms and has a rather wide bathymetric range between approximately -200~1500m. Unlike other members of genus Provocator it has a rather thick shell and no columellar folds, and is thus often placed in its own genus Iredalina. The protoconch is usually glazed over and forms a posterior spike-like structure, which varies in length and is rarely preserved completely. Two forms seem to exist: a more common form with sloped spire and more stout shell; and a rarer form with stepped spire and elongated shell (shown). Colour uniform, varying from pale to rather dark orange; a scarce white form occurs off Auckland Islands. Adults have thickened lip and the average shell length is about 100mm, but giants exceeding 160mm (with long, well preserved spike) are known to exist.

Buccinum mizutanii Habe & Ito, 1970 <br />
BUCCINIDAE<br />
-80m, Dredged, Off Kuril Islands, 1991, 77.5mm <br />
<br />
The "Mizutani's Whelk" is a uniquely sculptured cold-water buccinid ranging from Hokkaido, Japan to the Sea of Okhotsk. Whorls carry two prominent, thick spiral cords on the body whorl an additional weaker one on the base. The first cord below the shoulder is usually the strongest and is characteristically nodulose, giving it an unmistakable strongly wavy appearance. It is most similar perhaps to B. nodocostum Tiba, 1984, which shares the nodulose spiral cord but differs by the cords being more numerous and much narrower as well as less prominent. Buccinum opisoplectum Dall, 1907 and B. glaciale f. inclitum Pilsbry, 1904 are also similar but likewise these species also have more numerous, much narrower spiral cords and are easily separable. It appears to be a very rare species in the shell trade market. A carnivorous and scavenging gastropod, it inhabits muddy bottoms of rather deep water around -100~500m. Typical shell length around 90mm, very large specimens may reach 120mm. It is named in honour of Mr. Shosan Mizutani, a fisherman based in Abashiri, Hokkaido who first discovered this species.

2016年の一貝目は今年の干支「申」にちなんで、サルアワビ！この仲間は軟体が猿の尻のように赤いことから名付けられました。<br />
<br />
2016 is upon us, and it is a year of Monkey. The genus Scelidotoma is known as "Monkey Abalone" (saru-awabi) in Japanese as their soft parts are red, just like the bottoms of monkeys. Here's one from Japan to celebrate the arrival of a Monkey year! <br />
<br />
Scelidotoma gigas (Martens, 1881)<br />
FISSURELLIDAE<br />
-20~25m, Coast of Yagi, Hirono-cho, Iwate Prefecture, Japan, 82.3mm, F++, 2014/vii<br />
<br />
The "Giant Tugali Limpet" is a very large fissurellid native to northwest Pacific, with a distribution ranging from northern Korea and Japan (north of Fukushima Prefecture) to Sakhalin. A rather uncommon algae-grazing herbivorous species, it inhabits hard rocky substrates of intertidal to shallow subtidal waters down to about -30m deep. Although the shell is not colourful, its soft parts are vivid and brightly coloured in orange to red and the foot is larger than the shell. A shallow notch in the anterior end of the shell proves that it is a slit limpet, but this feature is often very inconspicuous in gerontic specimens. Typical shell length around 70mm, very large specimens may exceed 95mm. It used to be placed in the genus Tugali (hence the common name), but is now moved to Scelidotoma. Although the external appearance is similar to abalones, its flesh is said to taste bitter and vile when raw and tasteless when cooked. It is one of the host species of the symbiotic scale worm (Polychaeta: Polynoidae) Arctonoe vittata (Grube, 1855), which lives in the pallial groove of the host. The host helps the worm move about and protects it from predators, the worm does not feed on the host and in return helps the host fight off predators such as sea stars by biting them.

Thermosipho desbruyeresi (Okutani & Ohta, 1993) f. nipponensis (Okutani & Fujiwara, 2000)<br />
BUCCINIDAE<br />
-1002m, Iheya North Hydrothermal Field, Okinawa Trough, Japan, 80.2mm <br />
<br />
Thermosipho desbruyeresi is a large buccinid endemic to deep-sea hydrothermal vent fields. It has a wide distribution across Japanese vent sites in Okinawa Trough and Izu-Ogasawara Arc (depth range -600~1400m) and extending more than 8000km to Mariana, North Fiji and Lau Basins (depth range -1750~2750m). The Japanese population was described as a separate subspecies, T. d. nipponensis (Okutani & Fujiwara, 2000), but was later synonymised with T. d. desbruyeresi by Kantor et al (2013). A carnivorous / scavenging species, it has rather low population density and only rarely encountered especially in Okinawa Trough but is much more numerous in other localities. It is usually found on rock surfaces as well as in association with Bathymodiolus mussels which they feed on. The apex is always corroded away by the acidic flow of hydrothermal fluid, although the extent varies by locality and the acidity in the individual's microhabitat. The periostracum is often overlaid with various sulfide deposits from the vents, the extremeness of its habitat is evident. By far the largest gastropod native to Okinawa Trough hot vents, the average shell length is 70~80mm but giants may reach 100mm. It was originally described in the genus Eosipho, then considered to be an Enigmaticolus for a short period of time before the new genus Thermosipho was erected.

Bullia othaeitensis (Bruguière, 1789) <br />
NASSARIIDAE<br />
Masirah Island, Oman, 49.1mm <br />
<br />
Bullia othaeitensis is a very handsome nassariid characterised by numerous equally spaced spiral ridges. Native to Eastern Arabia with most specimens originating from Oman, the actual range may extend as far as Karachi, Pakistan. Its name is very confusing as although it is an arabian species, the specific epithet means "from Othaeite" with Othaeite being an alternative spelling of "Otaheite", an old name for Tahiti, French Polynesia. This is due to a mistake in recognising the origin of the type material, which unfortunately was not too uncommon back in the days when the accurate provinance for many species remained unclear for decades. In fact, the entire genus Bullia is absent from the Western Pacific. It is perhaps better known by the name Bullia tahitense (Gmelin, 1791) which is a junior synonym, and that name also means "from Tahiti". The two authors may have received material from the same lot with the same mistaken locality labels, especially considering the short time difference between the two descriptions, though this is merely speculation. The specific epithet is often misspelt in various ways, such as "otaheitensis" or "othaeitense". It is a very rarely available speices, mostly absent from collections. Fresh specimens carry sparse orange-brown axial flammules, though these fade over time. A carnivorous and scavenging gastropod, it inhabits sandy bottoms of shallow waters down to about -15m. Typical shell length around 30mm, very large specimens as shown may exceed 45mm.

Harpa doris Röding, 1798 <br />
HARPIDAE<br />
-2.5m (-8 ft), Dived by local person, On clean brown sand, Off Dakar, Senegal, 65.6mm <br />
<br />
The "Rosy Harp" is a lovely harpid ranging from Senegal to Angola, and is the only recent Harpa species in the Atlantic Ocean. It is characterised by radial bands of rectangular, rosy red patches that makes it an especially beautiful harp shell. The extent of red patches vary greatly among individuals and the synonym H. rosea Lamarck, 1816 is often used as a form name by collectors and dealers for exceptionally reddish specimens. Two distinct forms are known, the nominal form from coastal mainland Africa (shown) has thin, lightly constructed and more slender shells; whereas the form from Ascension Island and Cape Verde Islands are much more robust and shorter. The island form was initially described as a separate species, H. robusta Röding, 1798, and although regarded as a synonym today many feel it is still worthy of a subspecific rank if not a full species. Like all Harpa species it is a carnivorous and predatory gastropod that mainly feeds on small crustaceans, and inhabit shallow sandy bottoms to -30m depth. Typical shell length for the nominal form around 60mm, very large specimens may exceed 80mm; the island form is generally smaller and averages at around 40mm, though the largest specimens may exceed 70mm. It used to be a rarity before around 1980s when the Atlantic shells were less readily available, today it is regarded as a common species and has become easily obtainable.

Cardiomya behringensis (Leche, 1883) <br />
CUSPIDARIIDAE<br />
-350m, In shrimp traps, Off Teuri Island, Hokkaido, Japan, 2000/xi, 38.1mm <br />
<br />
Cardiomya behringensis is a rather solid medium-sized cuspidariid ranging from Honshu, Japan (both Pacific and Japan Sea) to Sea of Okhotsk to as far north as Bering Sea. Being a cuspidariid it is a carnivorous and predatory bivalve which hunts small animals, mostly crustaceans such as copepods and ostracods, using the inhalent siphon's suction power. It inhabits muddy bottoms of deep water around -200~450m deep, and is always covered by a layer of mud on top of the periostracum in natural condition. A very rare species, it is a celebrated collector's item among those who collect cuspidariid clams and difficult to acquire in collectible condition. Typical shell length around 20mm, very large specimens such as the one depicted may reach and exceed even 40mm.

Cuspidaria trosaetes Dall, 1925 <br />
CUSPIDARIIDAE<br />
-350m, In shrimp traps, Off Teuri Island, Hokkaido, Japan, 2000/xi, 28.5mm <br />
<br />
Cuspidaria trosaetes is a delicate, medium-sized cuspidariid from the Japan Sea, ranging from Hyōgo Prefecture to Hokkaido, Japan (and maybe the Kuril Islands). Like other members of Cuspidaria, it is a truly carnivorous and predatory bivalve that actively hunts small crustaceans (such as copepods and ostracods) using its inhalent siphon and trapping them in the mantle cavity. It inhabits a rather wide bathymetric range of around -50~650m, and is usually found on soft bottoms. It is characterised by a short, compressed posterior rostrum and a well inflated oval shell. The shell itself is white, with a greenish-brown periostracum which is thin and semi-transparent at first but increasingly thickens and as a result becomes more opaque in later stages. A rare species, it is very difficult to obtain a live-taken specimen in good condition. Typical shell length around 30mm, very large specimens may exceed 40mm.

Maurea tigris (Gmelin, 1791)<br />
CALLIOSTOMATIDAE<br />
New Zealand, 1960s, 62.0mm <br />
<br />
Delicately painted with alternating chestnut and pale yellow stripes, the "Tiger Maurea" is a beautiful endemic calliostomatid of New Zealand. It is the largest extant calliostomatid known to date, with the largest specimens reaching an impressive shell height of over 100mm, although vast majority are smaller and average at around 60mm. The largest specimens originate from off Three Kings Islands. The surface sculpture is fairly consistent, although the spire form varies from narrow conical to broad conical. The early whorls are almost always characteristically narrow and differ in sculpture from later whorls. Fully mature specimens have the inside of the outer lip noticeably thickened. The colouration pattern can vary quite a bit, for example many from off the Chatham Islands lack discrete axial bands with more scattered pattern, which was named as a subspecies C. tigris chathamensis (Dell, 1950) but now considered to be a synonym. It is a carnivorous grazer feeding on thecate hydroids and occur on rocky substrates from very shallow intertidal waters down to rather deep water around -200m. It is usually placed in the subgenus Maurea, which many consider worthy of a full genus rank.

Neancistrolepis glabra Habe & Ito, 1973 <br />
BUCCINIDAE<br />
-550~560m, 44°09.9'N 144°33.0'E, By deep-water whelk pot, Off Abashiri, Hokkaido, Japan, 1996/vii, 126.8mm <br />
<br />
Neancistrolepis glabra is a cold-water whelk with smooth, glossy periostracum ranging from Hokkaido, Japan to the Okhotsk Sea. A carnivorous and often scavenging gastropod, it inhabits sandy to muddy bottoms of deep water around -500~800m. A highly coveted species by collectors of Buccinidae, it is an extremely rare species on the international shell trade, especially adult specimens of decent quality. Even locally in Japan it is now quite a rarity, it was once only uncommon but now the supplies have effectively run dry. In fully adult specimens, the outer lip recurves slightly and characteristically flares out, extending anteriorly. The periostracum is often darker coloured in adults than juveniles and peels off rather easily when dried. The operculum is teardrop shaped and as usual for the genus Neancistrolepis it is much smaller than the aperture, though not as small as in the genus Parancistrolepis. Typical shell length around 110mm, very large specimens may exceed 140mm. It is one of only two currently recognised species in the genus Neancistrolepis, the other being N. beringianus (Dall, 1919).

Bolma johnstoni (Odhner, 1923) <br />
TURBINIDAE<br />
-90~120m, Trawled, Off N'zeto (aka. Ambrizete), Zaire, Angola, 48.4mm <br />
<br />
Bolma johnstoni is a stunning turbinid characterised by a well-developed, near-black basal callous which makes it unforgettable and unmistakeable. The shell surface carry scaly sculpture and a single row of rather long spines, the operculum is an attractive reddish-brown coloured one with a granulose central area. A famous endemic species of Angola, it is a rare species due to its restricted distribution and is much sought-after by collectors. It inhabits rather deep water around -70~120m, and although no reliable data exists regarding its detailed feeding behaviours it is almost certainly a grazer. Typical shell diameter including spines around 40mm, very large specimens may exceed 50mm. In the original description it was placed in the genus Astraea, and later moved to Bolma, its current genus. On dealers' lists and collection databases it is quite often misspelt as "Bolma johnsoni" (missing a "t" in the specific epithet).

Perotrochus pseudogranulosus Anseeuw, Puillandre, Utge & Bouchet, 2015 <br />
PLEUROTOMARIIDAE<br />
-300m, Trawled, Off Nouméa, New Caledonia, 2011, 41.0mm <br />
<br />
Perotrochus pseudogranulosus is a recently described medium-sized slit shell, previously confused with P. caledonicus Bouchet & Métivier, 1982. Due to the well-known existence of a "smooth" and a "pustulose" form with apparently no intergrades, there has been a long suspicion that Perotrochus species from around New Caledonia, previously all attributed to P. caledonicus, might actually be a species complex of at least two species. Indeed, an investigation using both morphology and molecular sequencing of the COI barcoding gene revealed in 2015 that the two were distinct species. The "smooth" form with unbeaded to weakly beaded spiral ribs but lacking in significant pustulation matches the type series of P. caledonicus, whereas the "pustulose" form with strongly beaded ribs is a separate species described as P. wareni Anseeuw, Puillandre, Utge & Bouchet, 2015. Surprisingly however, a further previously undescribed species was detected from the Coral Sea material -- P. pseudogranulosus. Perotrochus pseudogranulosus is rather similar to P. caledonicus but can be distinguished by a more conical shell with much more flattened basal disc, the presence of a characteristic strong metallic lustre on the shell surface, and a more regular "checkerboard" pattern under the selenizone. The spiral cords tend to be finely beaded, especially above the selenizone, hence the specific epithet. Phylogenetic reconstructions using the COI gene suggest it is in fact most closely related not to P. caledonicus but to P. deforgesi Métivier, 1990, which is sister to the P. caledonicus -- P. wareni group. The original description was based only from materials collected from the Coral Sea and restricted to the Chesterfield Plateau; but seeing a number of specimens has turned up in the shell trade throughout the past years with the locality data near New Caledonia, its true distribution may extend to as far as western New Caledonia. Presumably a carnivorous grazer feeding mostly off sponges like other pleurotomariids, it inhabits rather deep water around -300~500m deep. Typical shell diameter around 40mm, extremely large specimens may exceed 55mm. This species appears to be rare in the shell trade market, much rarer than either P. caledonicus or P. wareni, most likely due to its main habitat in the Coral Sea is too remote for regular visits to be made.

Neptunea nivea Okutani, 1981<br />
BUCCINIDAE<br />
-1300m, Cape Erimo, Off Shoya, Horoizumi District, Hokkaido, Japan, 2010/x, 104.4mm <br />
<br />
Despite its plain appearance, Neptunea nivea is a cold-water whelk most sought-after by collectors of the family Buccinidae, especially in Japan. This is because it is a bathyal species inhabiting very deep water around -1000~3000m, and as a result it very rarely appears on the market. A carnivorous and scavenging gastropod inhabiting soft muddy bottoms, it is supposedly endemic to a small part of Pacific Japan ranging from Miyagi Prefecture to southern Hokkaido, although its true range may extend to the Sea of Okhotsk. Most specimens have been obtained as trawl by-catches from either off Kinkasan, Miyagi Prefecture or Cape Erimo, Hokkaido. The shell is ornamented by indistinct spiral ridges which is weakest on the body whorl, and bear a thin layer of greenish brown periostracum which is usually almost completely eroded away in adult specimens. The apex is usually corroded to a certain extent; the operculum is smaller than the aperture although a certain variation is seen in its size relative to the aperture. Typical shell length around 100mm, extremely large specimens may exceed 140mm. It may be confused with Neptunea convexa Goryachev, 1978, but differs from it by having a more inflated shell, deeper suture, and relatively shorter spire. It has been placed by some authors, such as Higuchi, 2006, in the genus Tacita; but it is currently generally accepted to be a member of Neptunea.

Buccinum lamelliferum Lus, 1976 sensu Higuchi, 2006<br />
BUCCINIDAE<br />
-1300m, Trawled, Off Kinkazan, Miyagi Prefecture, Japan, 2006/vi, 99.0mm <br />
<br />
The true identity of this dignified, graceful, and spectacularly sculptured whelk has been much debated. This shell is characterised by three very strong, erected spiral keels (the third is below the suture line and may be very weak) and inhabit soft bottoms of great bathyal depths between -1000~3000m. It is an extremely rare shell especially in collectible condition, partly due to the great depths it dwells in; it is much sought-after among Japanese collectors. Vast majority of specimens have been collected off Miyagi Prefecture, Japan. The Japanese collector Shigeo Higuchi beautifully showed six specimens in his major publication "Northern Shells" (2006, Plate 107-108, "Higuchi shells" hereafter) and referred them to the name Buccinum lamelliferum Lus, 1976 after the specimen illustrated (Fig. 209, p. 498) in Prof. Takashi Okutani's "Marine Mollusks in Japan" (2001). There is a very similar species, Buccinum kashimanum Okutani, 1964, which is known to show vast variation between having no spiral keels and having as many as five spiral keels; but Higuchi deemed his specimens differed from B. kashimanum by the lack of conspicuous spiral threads which characterises B. kashimanum. This was true for Higuchi's specimens which only had very fine and discreet striations (as illustrated here). Interestingly however, the specimen in the Okutani book that Higuchi compared with actually has noticeable spiral threads like B. kashimanum and is thus probably actually a variation of that species. Furthermore, it was realised that the holotype of B. kashimanum has a similar sculpture with two storng keels and only very weak spiral striations. A comparison with the holotype of B. lamelliferum also reveals that the holotype actually has four spiral keels and appear quite different from the Higuchi shells (although some of the B. lamelliferum paratypes did have three keels their positions differed). Whether the true B. lamelliferum is actually also a synonym of B. kashimanum is an interesting question but fresh specimens from the type locality (off Kuril Islands) is required to shed further lights on this matter. The distribution range of the true B. lamelliferum is probably only north of Hokkaido, Japan to Kuril Islands; whereas the range of B. kashimanum is from Kashima-nada, Ibaragi Prefecture to Hokkaido, Japan. It therefore appears that the Higuchi shells is most likely not B. lamelliferum but either an extreme variation of B. kashimanum or an undescribed species; recent publications such as Hasegawa, 2009 and Higuchi, 2014 have adopted the former explanation and refer to the Higuchi shells as B. kashimanum VAR. Nevertheless, in the shell trade market (especially locally in Japan), the name B. lamelliferum still refer to this form (i.e., the Higuchi shell) and this is unlikely to change for sometime as this form is much rarer and fetch much higher prices than standard B. kashimanum (which is only somewhat uncommon in good condition). Typical shell length around 90mm, extremely large specimens may exceed 110mm.

Leptoconus kawamurai (Habe, 1962) <br />
CONIDAE<br />
Naze, Amami Ōshima, Kagoshima Prefecture, Japan, 1989/vii, 51.4mm <br />
<br />
The "Kawamura's Cone" is an elegant Western Pacific conid with a relatively tall spire and tent-like pattern. Although it is widely accepted to distribute in the Ryukyu Islands from the Amami Islands (type locality) to southern Okinawa, morphologically similar specimens have been taken from Taiwan and even as far as Guam. Vast majority of specimens are dead-collected from sands pumped up from a few dozen metres deep for making beaches and harbour works in Okinawa, such specimens are uncommon. Live specimens are extremely rare and it was once even believed to be an extinct species, but the first live specimen was obtained in 1989 from Naze, Amami Ōshima Island, followed by a few more. A carnivorous and predatory gastropod probably feeding mostly on other molluscs, it inhabits rather shallow waters up to 50m deep. It is a There is a long debate about whether it is a geographic subspecies/form of Leptoconus milneedwardsi (Jousseaume, 1894) or a separate species, although in the recent years it is generally treated as a full species in its own right. It differs from L. milneedwardsi by the consistently much smaller size (up to 100 mm vs up to 180 mm in shell length) and a much shorter spire. Typical shell length around 70mm, extrmely large specimens may exceed 90mm.

Cymbiola perplicata (Hedley, 1902) <br />
VOLUTIDAE<br />
Lihou Reef, Coral Sea, Off Queensland, Australia, 1995/xii, 73.0mm <br />
<br />
The "Entangled Volute" is a delightful volute characterised by stunning golden axial lines, and is a much sought-after rarity among the volutes. The original description was based on three poor beached shells from Australian fishermen, but with no further specimens being found its true provenance remained a mystery. That is, until its re-discovery in the late 1970s by Mr. Tom Nielson of Yeppoon, Queensland, Australia and his team. Nielson had already re-discovered other rare shells, including another rare volute Cymbiola thatcheri (McCoy, 1868), using special shell dredges in the early 1970s on-board the chartered boat "Coralita". His early searches for C. perplicata funded by Mr. John du Pont had ended in no avail, however; and it was only after repeated cruises (also on-board the "Coralita") that he finally managed to locate and collect live specimens of C. perplicata in the Coral Sea. His early expeditions were recorded in a film entitled "In Search of the Perplicata", though virtually no remaining copies of it appear to exist. Today it is known to be an endemic of the Australian Coral Sea, and remains rather scarce still. A carnivorous gastropod like all volutes, it inhabits sandy bottoms of shallow to moderate depths around -2~40m. Typical shell length around 65mm, extremely large specimens may exceed 90mm.

Morum dennisoni (Reeve, 1842) <br />
HARPIDAE<br />
-200~250m, Trawled, Cuba, 2000/x, 52.0mm <br />
<br />
A truly magnificent orange-red parietal shield ornamented with white pustulation makes "Dennison's Morum" one of the most beautiful Moruminae species. A classic Carribean rarity first described from John Dennison's cabinet, it was selected as one of S. Peter Dance's 50 "Rare Shells" (1969) and was virtually unobtainable until the late 20th century. Somewhat variable in size, colouration, extent of shield pustulation, and strength of shoulder spines. The general form varies also according to size, with larger specimens becoming more elongated with weaker shoulder spines. A carnivorous and scavenging gastropod inhabiting sandy to muddy bottoms, it is usually found in rather deep water around -50~200m deep. Its geographic range is quite wide, from North Carolina, USA to as far south as Brazil. Most specimens are caught as by-catches of shrimp trawlers. Today it is still somewhat rare, and due to the high demand large specimens in good condition continue to fetch considerable prices. Typical shell length around 45mm, extremely large specimens may exceed 65mm.

Hysteroconcha lupanaria (Lesson, 1831)<br />
VENERIDAE<br />
Guaymas, Mexico, 1968/x, 78.2mm<br />
<br />
The "Panamic Comb Venus" is an immediate standout among bivalves with two rows of long spines protruding from the posterior slope of each valve as it is very unusual for a non-spondylid bivalve to have long spines. Younger specimens tends to have longer, more intact spines; large specimens usually have most spines broken off. It is a locally common burrowing filter feeder living on sandy bottoms from intertidal to -5m depth, but due to its limited distribution specimens are uncommon on the shell trade market. Large specimens with good spines, especially, are quite rarely seen. In life it is buried with its long spines positioned upwards, possibly used as a defence against predators. Distributed in the Eastern Pacific Ocean from Mexico to Peru, it is very similar to its congeners H. dione (Linnaeus, 1758) and H. multispinosa (Sowerby II, 1851). Hysteroconcha dione tends to have shorter spines and is distrubuted only in the Western Atlantic Ocean, whereas H. multispinosa is also an Eastern Pacific species but has more prominent, erect ribs and more numerous spines. Typical shell length without spines about 40mm, extremely large specimens may exceed 65mm and length including spines may exceed 90mm. It has long been placed in the genus Pitar, and is still often seen listed under that genus.

Tropidophora deburghiae (Reeve, 1861) <br />
POMATIIDAE<br />
High in tree tops, About 50km into mountainous primary forest accessible only by muddy trail, 40+ km north of Mananara on road to Maroantsetra, Coastal northeast Madagascar, 2000/x, 47.9mm <br />
<br />
A truly eccentric combination of shape and pattern makes "Mrs. de Burgh's Torpid" one of the most outstanding and famous out of many landsnail species endemic to the great island of Madagascar. It is endemic to northeastern Madagascar, living deep in rainforest and high on tree tops, making it a difficult species to collect. An assessment by the IUCN in 1996 concluded that it was an endangered species and although it is still considered rare and endangered today, little further information have become available to provide a reliable update on the current status of its population. The shell form is little-varied although the pattern vary slightly among specimens. It is often seen listed under the family Pomatiasidae, but Pomatiasidae is currently considered to be a junior synonym of Pomatiidae. Although a landsnail, its chalky operculum reveals its systematic position in the superfamily Littorinoidea, meaning it is in fact a close relative of periwinkles which have managed to invade the terrestrial ecosystem. Typical shell diameter around 45mm, very large specimens may exceed 55mm.

Perotrochus vicdani Kosuge, 1980 <br />
PLEUROTOMARIIDAE<br />
-200~250m, Balut Island, Davao Occidental, Mindanao, Philippines, 2008/x, 56.0mm <br />
<br />
The "Victor Dan's Slit Shell" is a vibrant light-weight Western Pacific pleurotomariid ranging from the Philippines to Vietnam, although vast majority of specimens known originate from the Philippines. It was the first extant slit shell species to be discovered in the Philippines, being described ten years earlier than Mikadotrochus gotoi (Anseeuw, 1990). The form is quite variable in terms of spire height and steppedness, and so is the colouration in terms of strength of redness as well as the amount of flammules. Specimens from the area between Balicasag and Siquijor tends to have more intense red colour than usual. A carnivorous grazer feeding mostly on sponges, it inhabits rather deep water around -100~400m in depth. Typical shell diameter around 50mm, extremely large examples are known to exceed 70mm. Although it used to be a very rare species in the past, thanks to deep-water tangle nets smaller sized specimens are only uncommon nowadays, although large specimens over 55mm in shell diameter remains scarce. It is named in honour of Mr. Victor Dan, a famous shell enthusiast, collector, and dealer based in the Philippines.

Bayerotrochus africanus (Tomlin, 1948) <br />
PLEUROTOMARIIDAE<br />
-300m, Trawled, Off Durban, Natal, South Africa, 1986/x, 116.7mm <br />
<br />
The "African Slit Shell" is a large, light weight pleurotomariid native to eastern and southern Africa, ranging from around Mozambique to South Africa. Most specimens originate as trawl by-catch off South Africa, and it appears to be an uncommon species. It is quite variable in colouration of the flammules, ranging from pale to deep red. A carnivorous grazer feeding mostly on sponges like other slit shells, it inhabits sandy to muddy bottoms of rather deep water around -150~400m in depth. It is quite similar to its common congener B. teramachii (Kuroda, 1955) found in the western Pacific, but has a more strongly stepped spire and its spiral striations are much less beaded compared to B. teramachii. The shell therefore typically appear broader and smoother with higher gloss than B. teramachii. Although B. teramachii has been considered to be its subspecies in the past, both are currently recognised as separate species in their own right. Typical shell diameter around 110mm, though very large specimens may exceed 130mm.

Lyncina kuroharai (Kuroda & Habe, 1961) <br />
CYPRAEIDAE<br />
-150m, Trawled, Okinoshima, Munakata, Fukuoka Prefecture, Japan, 1980/vii, 40.1mm <br />
<br />
The "Kurohara's Cowrie" is a lovely medium-sized cypraeid ranging from Honshu, Japan to East China Sea to Taiwan. A classic rarity among Western Pacific cowries, it can be safely separated from other superficially similar Lyncina species such as L. schilderorum Iredale, 1939 and L. sulcidentata (Gray, 1824) by its very fine teeth, curved aperture, and inflated shape. It is a omnivorous grazer living among sponges and rubbles, usually in relatively deep water around -50~250m, although it is occasionally found as shallow as -10m. Very rarely such specimens are washed up on the beach, becoming a rare trophy of beachcombers. Though in recent years Chinese trawlers have brought up numerous specimens from the East China Sea making it much easier to acquire, it is very prone to imperfections such as growth scars and octopus holes and perfect specimens are still very scarce today. Typical shell length around 40mm, extremely large specimens are known to exceed 60mm. It is named in honour of Kazuo Kurohara of Japan.

Mikadotrochus beyrichii (Hilgendorf, 1877) <br />
PLEUROTOMARIIDAE<br />
-100~120m, Trawled, Off Mimase, Kōchi, Kōchi Prefecture, Japan, 1969/vi, 84.4mm <br />
<br />
The "Beyrich's Slit Shell" is a striking pleurotomariid endemic to Japanese waters, best known from the central portion of Honshu Island. Although the third to be formally described it is actually the earliest living slit shell recorded and illustrated in the recent literature, being included in Japanese books such as "Kigai-zufu" (Kenkado Kimura, 1775) and "Mokuhachi-fu" (Sekiju Musashi, 1843) long before Perotrochus quoyanus (Fischer & Bernardi, 1856) was discovered in the Caribbean Sea. These Japanese books were unknown to scientists outside the country then, however. This species was thus overlooked until Franz Martin Hilgendorf (1839-1904), a German zoologist, found a specimen in a souvenir shop of Enoshima, Kanagawa Prefecture, Japan in 1876. He described it the following year, naming it after Heinrich Ernst Beyrich (1815-1896), a famous German palaeontologist who first proposed the term 'Oligocene'. It has traditionally been a greatly celebrated rarity, especially among Japanese collectors, and remains scarce nowadays. After Hilgendorf reported its existence the British Museum (Natural History) in London commissioned the University of Tokyo to find a specimen. It was the eminent professional marine animal gatherer Kumakichi Aoki (1864-1940), working for the Misaki Marine Station, who successfully collected a living specimen in the following spring. He was rewarded with the prize of 40 Japanese yen, a huge sum back then. Upon receiving the prize Aoki supposedly exclaimed "I've become a millionaire!", which leads to this species being sometimes called "Cho-ja-gai" (Millionaire Shell) in Japan, even today. A carnivorous grazer feeding on sponges, it usualy inhabits rocky bottoms around 100~300m deep but has been found as shallow was -30m, making it the shallowest living of all recent pleurotomariids. Strong, broad radial lirae on the shell surface are crossed by relatively infrequent axial ribs to generate the characteristic coarsely chequered sculpture. The frequency and extent of red flammules vary according to localities, with specimens from Chiba Prefecture and Tokyo Bay having the darkest colouration. The shell form also vary somewhat by locality, for example shells from Kōchi Prefecture (shown) are usually broader than typical specimens from Chiba Prefecture. Typical shell length around 70mm, very large specimens may exceed 100mm.

Perotrochus atlanticus Rios & Matthews, 1968 <br />
PLEUROTOMARIIDAE<br />
-200~250m, Trawled, Off Cabo de São Tomé, Rio de Janeiro, Brazil, 1998/x, 62.5mm <br />
<br />
The "Atlantic Slit Shell" is a gorgeous medium-sized pleurotomatiid endemic to southern Brazil, from around Rio de Janeiro to as far south as the Brazil-Uruguay border. The shell is heavily ornamented by finely beaded coarse spiral cords and numerous flammules, the colouration of which vary from red to brown and the saturation vary from one specimen to another. The characteristic shape of adult shells is formed by the gradual shifr of the whorls being smooth-sided, as in the early teleoconch, to strongly inflated and bulging ones in the later stages. It is locally only uncommon and is perhaps the most easily obtainable Atlantic slit shell, although it is very susceptible to erosion and bore-holes, specimens in fine conditon are thus still considerably rare. A carnivorous grazer feeding on sponges, it inhabits sandy to muddy bottoms of rather deep water around -150~300m. Typical shell diameter around 65mm, extremely large specimens are known to exceed 85mm. The spire is variable in height although usually it is usually low; the name Perotrochus notialis (Leme & Penna, 1969) refers to a high-spired form and is now considered to be a junior synonym.

Halicardia nipponensis Okutani, 1957 <br />
VERTICORDIIDAE<br />
-500~600m, Trawled, Off Sōma, Hamadōri, Fukushima Prefecture, Japan, 2006/viii, 32.0mm <br />
<br />
The exceptionally exquisite Halicardia nipponensis, with its unique shape formed by two strong radial ridges, is certainly one of the most unusual bivalves of all. It is a carnivorous bivalve inhabiting muddy bottoms of deep-water ranging from -500~1500m, and feeds on small invertebrates such as copepods by capturing them using mucus-lined tentacles. It is a renowned endemic of Japan only found off the northern half of the Pacific Honshu. An incredibly coveted species, especially in Japan where its beauty is greatly celebrated, it is only very rarely obtained by deep-water trawling and command high prices. When seen from the anterior view its shape resembles two hearts, the interior also carry heart-shaped hinge tooth. Futhermore, its side views are strongly reminiscent of the kanji (Chinese character) for "heart". It is therefore known in Japan as the "Nippon-otohime-gokoro" (literally, "Heart of the Japanese Maiden Princess"), aptly named by Prof. Takashi Okutani. This brilliant wamei (Japanese name) is part of the reason why it is an especially popular shell in Japan. Although its congener Halicardia maoria Dell, 1978 from New Zealand is tentatively reported to be associated with deep-sea hydrocarbon seeps, it is unclear whether H. nipponensis does the same. Typical shell length around 32mm, extremely large specimens are known to exceed 40mm.

Perotrochus quoyanus (Fischer & Bernardi, 1856) <br />
PLEUROTOMARIIDAE<br />
-200~210m, Collected by submersible, Off Sandy Lane Bay, Barbados, 1998/vi, 52.4mm<br />
<br />
First discovered by Commandant Beau in the Marie-Galante Island, Guadeloupe in 1855, the legendary "Quoy's Slit Shell" was the first living pleurotomariid species formally exposed to science. The encounter of this species is among one of the most important landmarks in malacology and generated great excitement, as previously this important ancestral lineage of basal gastropods were considered long extinct; the finding of living species opened up wholly new possibilities in studying the evolution of gastropods. It was therefore selected as one of S. Peter Dance's 50 "Rare Shells" (1969). The first specimen (i.e., the holotype) was taken from a fisherman's pot set in deep-water, and it was inhabited by a hermit crab. This was closely followed by the exposure of Entemnotrochus adansonianus (Crosse & Fischer, 1861) and Mikadotrochus beyrichii (Hilgendorf, 1877), up until now some 30 living pleurotomariid species have been described. In fact, M. beyrichii was illustrated in the Japanese books such as "Kigai-zufu" (Kenkado Kimura, 1775) and "Mokuhachi-fu" (Sekiju Musashi, 1843) long before the detection of P. quoyanus, but these books was not known to scientists in the western world then. Today, P. quoyanus is known to have a rather wide distribution around the Caribbean Sea from Yucatan, Mexico to Virgin Islands to Venezuela. Furthermore there is one recognised subspecies, P. quoyanus insularis Okutani & Goto, 1985, described from the Bermuda Islands and has a much taller spire with more swollen whorls. Specimens with a similar form has since been found as far as Honduras, however. The name Perotrochus gemma Bayer, 1965 was previously considered to be a separate species but is now regarded as a gemmate form of P. quoyanus and thus a junior synonym of it. The shell is therefore rather variable in spire height and strength of surface sculpture (i.e., 'gemmation'), the colouration is also variable from rather pale to strongly flamed with reddish axial bands. It is a carnivorous grazer feeding mostly on sponges and usually inhabit hard substrates in deep water around -180~350m. Due to its deep habitat it is still a rare shell, especially live-collected in fine conditon; such shells are virtually only obtainable using deep-water submersibles as trawls rarely operate near the rocky walls it inhabit. Typical shell length around 45mm, extremely large specimens may exceed 60mm.

Mikadotrochus salmianus (Rolle, 1899) <br />
PLEUROTOMARIIDAE<br />
-240m, Trawled, Off Tosa, Kōchi Prefecture, Japan, 1967/vi, Ex-Coll. Helen Boswell, 116.2mm <br />
<br />
The "Salmiana Slit Shell" is an elegant pleurotomariid with a blazing coluration and a characteristically tall spire, ranging from Honshu, Japan to Taiwan to Philippines. A much sought-after rarity, most specimens have generally come from Taiwan although recently Chinese fishermen have also trawled many (mostly poor) specimens from the East China Sea. It reaches the largest size in Tosa Bay, Japan where the shells are the thickest and with a rather pale colouration; the shells gradually thins down towards south with specimens from the Philippines being the lightest in build but with a dark colouration. Both Tosa Bay and Philippines specimens are still very scarce today, especially in large size, though in the East China Sea it is probably best described as uncommon. A carnivorous grazer feeding on sponges, it inhabits hard substrates of rather deep water around -100~400m. Typical shell length around 90mm, extremely large specimens are known to exceed 135mm. For many decades since its description it was confused with its congener Mikadotrochus beyrichii (Hilgendorf, 1877) due to the small quantity and poor quality of available specimens. As better specimens surfaced, however, its obvious differences with M. beyrichii quicky became apparent and it has become widely accepted as a valid species since the 1970s. A well-known synonym is Mikadotrochus schmalzi Shikama, 1961.

Entemnotrochus adansonianus (Crosse & Fischer, 1861) <br />
PLEUROTOMARIIDAE<br />
-120~130m, Collected by submersible, Off Half Moon Bay, West End, Roatán Island, Bay Islands, Honduras, 2009/ix, 129.3mm <br />
<br />
The majestic and magnificently flamed "Adanson's Slit Shell" is perhaps one of the most beautiful pleurotomariids, and also a renowned and celebrated classic rarity among them. As the first of S. Peter Dance's 50 "Rare Shells" (1969) a photo of one of the oldest surviving specimens, purchased by Samuel Archer in Barbados in the 1800s, serves as the book's cover. A rather widely ranging species in the western Atlantic Ocean, it is best known from the West Indies and Caribbean Sea but the full geographical distribution ranges from as far as Bermuda down to Brazil. Specimens from Bermuda differs from all others in having a more vertically compressed shell of much smaller size (to 100mm), the spire also appears much more strongly stepped as the whorls are strongly shouldered. These Bermudian specimens are thus separated as a valid subspecies, E. adansonianus bermudensis Okutani & Goto, 1983. It is a carnivorous grazer feeding on sponges like the majority of pleurotomariids, and inhabits vertical rocky walls of rather deep water around 100~300m in depth. Even with all these knowledge about its ecology it is still a very rare shell on the international market nowadays because the steep rock walls it inhabit is well protected from traditional fishing methods. Dredging or trawling only uncover dead-taken or crabbed specimens, and traps have been effective in gathering only crabbed shells. Most live-taken specimens in fine quality, like the one shown, have therefore been carefully collected by underwater submersibles. The subspecies E. a. bermudensis is rarer still, with virtually no live taken examples so far known. The pattern is somewhat variable, although most specimens carry alternating red and pale patches. Large specimens tends to have less sharp, saturated colouration. Typical shell diameter around 110mm, although extremely large examples are known to reach a staggering size of 190mm. It is the second largest of all living slit shells, only surpassed by its Pacific congener E. rumphii (Schepman, 1879). Currently these two species are the only recognised valid species of the genus Entemnotrochus.

Kendrickiana veitchi (Smith, 1971) <br />
PENICILLIDAE<br />
Low tide, Broome, Kimberley, Western Australia, Australia, 203.1mm <br />
<br />
The "Veitch's Wateringpot" is a strange and wonderful penicillid endemic to Western Australia and Southern Australia, Australia; best known from the Great Australian Bight. It is a member of the bivalve superfamily Clavagelloidea, characterised by their remarkable behaviour of switching from growing the true shell to building a calcareous tube, called the adventitious tube. At the earliest stages of life after settlement it bears a normal bivalved shell, which is still attached to the outside of the adventitious tube and visible; although in this species it is largely incorporated into the tube. Uniquely among penicillids its adventitious tube is strongly bulbous at the "watering-pot" end, divided into hundreds of small tubes, and is not distinctively fringed like most other species. A filter-feeding species, it appears to be restricted to soft bottoms of seagrass beds (such as Posidonia sp.) and inhabit subtidal waters down to about 50m deep. In life it lives vertically buried with the "watering-pot" end down. Although probably only uncommon locally, it is rarely seen in the international shell trade market. Previously it has been placed in the genus Brechites and then Foegia, but after detailed anatomical investigation a new genus, Kendrickiana, was erected to house it; it is currently the only species placed in that genus. Typical length of the adventitious tube around 200mm, although very large specimens are known to exceed even 370mm.

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