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.

Lyria cloveriana Weaver, 1963 <br />
VOLUTIDAE<br />
-20~25m, From net of local fisherman, Tangalla, Sri Lanka, 89.4mm, F+, 2014/vi<br />
The "Clover's Lyria" is a pleasing and well sought-after volute endemic to Sri Lanka. A carnivorous and predatory gastropod, it inhabits sandy to muddy bottoms of moderate depths around -20~80m. Although once ago a rare species, it is only somewhat uncommon today thanks to many being bought up as by-catch of local fisheries. The shell is rather variable in stoutness but general pattern and the characteristically bulbous protoconch are distinctive features. Typical shell length around 75mm, giant specimens are known to surpass 95mm. It was named after the renowned American conchologist and shell dealer Phillip W. Clover, who is still very much active today.

Provanna glabra Okutani, Tsuchida & Fujikura, 1992 <br />
PROVANNIDAE<br />
-1150m, Cold seep site, Off Hatsushima, Sagami Bay, Japan, 10.9mm, F++<br />
Provanna glabra is a small provannid endemic to the cold seep chemosynthetic ecosystems of Sagami Bay, Japan; and is known from three sites including off Hatsushima, Sagami Knoll, and Okinoyama Bank. With an average density of 300 individuals per square metre, it is the most abundant megabenthos of the Sagami Bay seeps and is usually found on or around large bivalves especially Calyptogena spp.. It is considered a grazing gastropod ingesting bacterial mats and detritus, and is only found in deep to bathyal depths ranging between -800~1500m. Although for many years the Provanna populations in the hydrothermal vent fields of Okinawa Trough　were also attributed to this species, recent genetic investigations and in-depth morphological comparisons revealed them to represent a separate new species which is currently under description. The spire is always corroded away and the periostracum varies from olive to dark brown in colouration. Typical shell length around 10mm and very large specimens may exceed 13mm; giant specimens do exist but these often have very corroded spire and thus shell length is not a truly reliable size measurement for this species.

Vasum rhinoceros (Gmelin, 1791) <br />
TURBINELLIDAE<br />
SCUBA dived, On shallow reef, Off Nungwi, Zanzibar Island, Tanzania, 82.4mm, F++, 2011<br />
The "Rhinoceros Vase" is a very thick and heavy vase shell endemic to a small part central east Africa, ranging from Kenya and Tanzania including Zanzibar Island. It is a carnivorous and predatory gastropod primarily feeding on polychaetes and sipunculans. A shallow water dweller, it may be found from intertidal waters down to approximately -20m deep and inhabits sandy to rocky to weedy bottoms just within fringing coral reefs. Although a locally common species, it is uncommon on the market due to its restricted range. It is generally a rough shell and is very variable in pattern and form, especially knobbyness. The depicted specimen is a particularly spiny form known only from Tanzania which strongly reminiscent of the rare Vasum stephanti Emerson & Sage, 1988 from Somalia. There is also a rare golden form endemic to Zanzibar Island with a uniformly yellow shell and a golden columella, lacking the usual brown pattern. In some geronic specimens the anterior part of the outer lip strongly flares. Typical shell length around 70mm, very large specimens are known to exceed 100mm.

Murex echinodes Houart, 2011 <br />
MURICIDAE<br />
Beached, Between Ras Al Sawadi and Dibah, Gulf of Oman, Oman, 116.5mm, Dead/F+<br />
Murex echinodes is a recently described Murex species endemic to a small part of northwest Indian Ocean, from Gulf of Oman to Kuwait. It is part of a complex which also includes Murex scolopax Dillwyn, 1817, Murex somalicus Parth, 1990, and Murex megapex Neubert, 1998; and was considered as a form of M. scolopax until 2011 when Roland Houart remarked on their consistent differences and described it as a new species. Adult specimens are most easily differentiated from M. scolopax by the existence of a short but obvious second primary spine (P2 sensu Merle, 2005), which is lacking in adult M. scolopax (also M. somalicus). Compared to the very rare M. megapex only known from the types, it has a much smaller protoconch with less whorls (1.6-1.75 vs 3 in M. megapex) and lacks the lattice sculpture on the earlier whorls. There are many more intriguing distinctions between the species in this complex listed in the description paper (Houart, 2011) such as ontogenic differences, readers are referred there for further information. It is a carnivorous and predatory gastropod inhabiting shallow water from the very low tide zone to about -50m deep, and is uncommon to rather rare. The colouration is white to light tan, fresh collected specimens often have brown flammules all over the shell. Typical shell length around 110mm, very large specimens may exceed 150mm.

Busycon coarctatum (Sowerby I, 1825) <br />
BUCCINIDAE<br />
-80m, Trawled on muddy sand bottom, Cabo Catoche, Yucatán Peninsula, Quintana Roo, Mexico, 113.9mm, F+/F++, 2007/i<br />
The handsome "Turnip Whelk" is a Busycon whelk with stunning flame patterns, endemic to the Yucatan Penninsula and Bay of Campeche in Mexico. It is a classic rarity selected by S. Peter Dance as one of his 50 "Rare Shells" (1969), the first traceable specimen appeared in the early 19th Century and was in the collection of Charles Bennet (ie. the 4th Earl of Tankerville). After the death of Tankerville this specimen became the basis for its description (ie. the holotype) by Sowerby I in 1825, but for 125 years after the description it was so rare that "money could not buy it". Although it has become more available today it is still a rarely offered species and very uncommon in collections, especially so outside North America. It is a carnivorous and scavenging gastropod inhabiting moderately depths around -40~120m; most specimens are trawled on sandy to muddy bottoms. A little-varied species, its squat whorls and the narrowly confined anterior siphonal canal are unique among the genus Busycon and makes it unmistakable. Typical shell length around 130mm, very large specimens may exceed 180mm.

Margarites shinkai Okutani, Tsuchida & Fujikura, 1992 <br />
MARGARITIDAE<br />
-860m, Cold seep site, Off Hatsushima Island, Sagami Bay, Kanagawa Prefecture, Japan, 13.2mm, F++<br />
Margarites shinkai is a deep-sea margaritid top shell endemic to chemosynthetic environments of Japan. Remarkably it is able to live in both cold seep and hydrothermal vent fields, and is hitherto known from cold seep sites of Sagami Bay and the Izena Cauldron hydrothermal vent field of Okinawa Trough. Its distribution is disjunct as it is not found in other chemosynthetic sites between these two localities approximately 1500km apart, and may indicate requirement of specific environmental conditions or poor sampling of some sites. Considered to be a grazer of microbial mat and detritus, it is found living on and around large chemosynbiotic bivalves such as Calyptogena spp. in bathyal depths around -1100~1400m. The shell is a beautiful silvery grey with about 10 fine spiral ridges and show prismatic reflections under light, the periphery is angulated. It is named after the manned research submersible "Shinkai 2000" which first discovered it; the word "shinkai" meaning "deep-sea" in Japanese. Typical shell length around 15mm, very large specimens may exceed 20mm. It may be differentiated from the other congeneric chemosynthetic gastropod M. ryukyuensis Okutani, Sasaki & Tsuchida, 2000 by its much weaker sculpture, more compressed shell, larger umbilicus, and radula characteristics (8 laterals vs 10 in M. ryukyuensis).

Tellina foliacea Linnaeus, 1758 <br />
TELLINIDAE<br />
-2~5m, Phi Phi Islands, Krabi Province, Thailand, 94.2mm, F+, 2012<br />
The "Foliated Tellin" is an extremely beautiful tellinid ranging from Amami, Japan to Philippines to northern Australia. Famous for its wonderful colouration resembling that of autumn leaves or the sunset, it is widely coveted by beachcombers and shell collectors alike. It is a filter-feeding and burrowing bivalve inhabiting shallow sandy bottoms around -2~30m deep, freshdead shells are regularly washed up on the beach. It is quite common throughout its distribution, most specimens originate from Thailand and Philippines. It is currently placed in subgenus Phylloda, which some authors consider a full genus. Typical shell length around 75mm, very large specimens may exceed 110mm.

Tellina spengleri Gmelin, 1791 <br />
TELLINIDAE<br />
Very low tide, Sand flats, Andaman Sea, Trang Province, Thailand, 67.5mm, F++, 2012<br />
The "Spengler's Tellin" is a curiously shaped Western Pacific tellinid ranging from Okinawa, Japan to around Borneo and Indonesia. The two valves are strongly bent in the opposite direction and it is thus arc-shaped when viewed from the umbo. The shell is intricately sculptured with numerous strong concentric and ending in a row of spines in the posterior angle, as well as more rows of spines on the posterior slope and the anterior-dorsal edge. A common burrowing filter-feeding bivalve inhabiting sandy to muddy bottoms of shallow water from low tide zone to about -20m, shells are often washed on shore after the animal dies. Typical shell length around 60mm, very large specimens may exceed 80mm.

Calyptogena (Phreagena) soyoae Okutani, 1957 <br />
VESICOMYIDAE<br />
-1167m, Cold seep site, Off Hatsushima, Sagami Bay, Japan, 91.5mm, F++, 1990s<br />
Calyptogena soyoae is a large vesicomyid endemic to cold seeps and perhaps the most famous chemosynbiotic bivalve of the western Pacific. First described in 1957 by the eminent malacologist Prof. Takashi Okutani using dead shells from Sagami Bay, live specimens were not known until 1984 when the first chemosynthetic ecosystem was accidentally discovered in Japan: a cold seep site off Hatsushima, Sagami Bay characterised by a great density of this clam. For a long time it was considered endemic to Sagami Bay, in seepage sites off Hatsushima Island, Okinoyama Bank, and Sagami Knoll ranging from -750~1200m in depth (type specimens are dead collected from -750m, off Jogashima Island but this site is not well-explored); but recent genetic studies indicate that Calyptogena (Phreagena) kilmeri Bernard, 1974 from seeps of British Columbia, Canada to Monterey Bay, USA is actually the same species and a junior synonym. Furthermore, population genetics analyses also revealed a cryptic species complex involving a morphologically very similar but genetically separated sister species Calyptogena (Phreagena) okutanii Kojima & Ohta, 1997 which has wider distribution and is also capable of inhabiting hydrothermal vents in Okinawa Trough. The two sister-species lives mixed in Sagami Bay seeps (ratio is about 1:3 for C. soyoae : C. okutanii) and are probably reproductively isolated. Compared to C. soyoae, C. okutanii generally has a more elongated shell with a stronger excavation and keel in the middle of each valve. It has a much enlarged gill housing sulphur-oxidising chemosymthetic endosymbionts and relies on these for nutrition; the digestive tract is reduced. It lives buried in sediments and extends the foot deep into the sediment to extract hydrogen sulphide for the endosymbionts. As the microdistribution of seepage activity changes from time to time it is capable of crawling around using its powerful foot to locate spots with sufficient hydrogen sulphide input and is thus surprisingly mobile. The animal is blood-red in appearance due to its usage of haemoglobin for oxygen carrier. Its rather thick periostracum is yellowish brown to dark brown, and is mostly corroded away in the earlier parts of the valves. Although locally common, its extremely restricted habitat makes it very difficult to obtain. Typical shell length around 100mm, very large specimens may attain 130mm. It is named in honour of the Fisheries Research Agency (Japan) research vessel "Soyo-Maru" which trawled the type specimens.

Acesta philippinensis (Bartsch, 1913) <br />
LIMIDAE<br />
-1000m, Trawled by fisherman, South China Sea, China, 211.4mm, F+/F++, 2005<br />
The "Philippines Giant Lima" is a spectacular deep water Western Pacific limid ranging from Honshu, Japan to Taiwan to East and South China Seas to Philippines to Borneo. Populations from the northen half of the distribution (South China Sea being the boundary) has wider, heavier valves and slight differences in sculpture (such as the depicted specimen); these were given the name A. marissinica (Yamashita & Habe, 1969) which is regarded as a form and junior synonym of A. philippinensis today. It is a filter-feeding bivalve inhabiting sandy to muddy bottoms of deep to very deep water around -200~1200m, mostly from -400~1000m. Although actually locally common especially in East and South China Sea, it is quite uncommon on the market due to the depth; it is also a rough species and quality specimens are difficult to obtain. Typical shell length around 160mm, very large specimens may attain 220mm.

Astralium calcar (Linnaeus, 1758) <br />
TURBINIDAE<br />
-5m, Dived on rock, Olango Island, Central Visayas, Philippines, 53.5mm, F++<br />
The "Wheel-like Star" is a handsomely spinous turbinid ranging from Okinawa, Japan to Philippines to Malaysia to Queensland, Australia. An algae-grazing gastropod inhabiting mostly hard substrates such as rocks, it is a very common shallow water dweller inhabiting very shallow intertidal water to about -30m deep. The number of spines per whorl may vary from eight to 14; the length also vary greatly and long-spined specimens are often referred to as A. calcar f. aculeatus (Gmelin, 1791). In natural condition it is almost always heavily encrusted by various overgrowth and cleaning can be a time consuming and laborious task. Typical shell diameter around 35mm, very large specimens may reach 60mm.

Bathymodiolus marisindicus Hashimoto, 2001 <br />
MYTILIDAE<br />
-2770m, Dragon Hydrothermal Vent Field, Southwest Indian Ridge, 110.7mm, F+, 2012/xi<br />
Bathymodiolus marisindicus is a large deep-sea mussel endemic to the hydrothermal vents of Indian Ocean, ranging from Kairei, Edmond, and Solitaire fields in the Central Indian Ridge to Dragon Field in the Southwest Indian Ridge; the depth range is approximately -2400~3300m. Characterised by a very dark periostracum covered by thick, rusty deposit of hydrothermal origin. Recent genetic studies have shown that it is in fact very closely related to congeners B. brevior von Cosel, Métivier & Hashimoto, 1994 from North Fiji and Lau, as well as B. septemdierum Hashimoto & Okutani, 1994 from the Izu-Bonin-Mariana Arc; these are likely to be populations of one extremely wide-ranged species and if so the name retained will be B. septemdierum which was published a month earlier than B. brevior. As is the norm for bathymodiolins it harbours chemosynthetic endosymbionts, sulphur-oxidising bacteria in this case, in its much enlarged gill and relies on these for nutrition, the digestive tract is very much reduced. It forms dense aggregations some distances away from the active venting orifices and on diffuse flow sites, although it is locally common it is virtually unobtainable due to its very restricted range and inaccessible depth. Typical shell length around 100mm, large specimens may exceed 130mm.

Circomphalus yatei (Gray, 1835) <br />
VENERIDAE<br />
Mahurangi Regional Park, Auckland, North Island, New Zealand, 52.2mm, F+/F++, 1988/vii<br />
The "Frilled Venus" is a delicately stunning venerid endemic to New Zealand, found around North, South, and Stewart islands. It is a filter-feeding species inhabiting sandy bottoms with a narrow bathymetric range around -5~15m in the shallow water. Although locally common, clean specimens with mostly intact frills are uncommon. Somewhat variable in frequency of the concentric ribs; and the colouration may range from off-white to yellowish or reddish brown. It is often washed ashore in considerable numbers after the storm but majority of such specimens have been badly damaged by the time they reach the beach. Typical shell length around 50mm, extremely large examples may attain 65mm. It is still often seen placed in its old genus Bassina.

Swiftopecten swiftii (Bernardi, 1858) <br />
PECTINIDAE<br />
-50m, Trawled on mud and seaweed bottom, Japan Sea, Japan, 103.9mm, F++, 2014/viii<br />
The "Swift's Scallop" is a colourful and attractive medium-large pectinid distributed from Japan Sea to northeast Japan to Sakhalin, Russia. Although quite distinctively shaped, it is very variable in knobbiness depending on number of growth pauses the specimen has had, each pause forming a row of knobs. The colouration may differ from bright yellow to purple to red to dark brown, and it is very popular among collectors for this reason. In the most frequent colouration (shown), the left valve is a reddish purple and the right valve is white. A common filter-feeding bivalve, it inhabits mostly rock and gravel bottoms of shallow water from lowtide depths down to about -50m. Typical shell length around 80mm, very large specimens may exceed 120mm. It is considered a delicacy in the Japonic region, particularly Hokkaido where it is fished and eaten along with Mizuhopecten yessoensis (Jay, 1857).

Stellaria paucispinosa Kosuge & Nomoto, 1972 <br />
XENOPHORIDAE<br />
-40~60m, Tôlanaro (ie. Fort Dauphin), Madagascar, 100.6mm, 2014<br />
The "Sun Carrier" is an unforgettable xenophorid resembling closely a stylised drawing of the sun. Adults produce long radial spines in regular frequency in place of various foreign materials such as shells and rocks often seen in other members of the family; although juveniles do actually exhibit this behaviour, not all specimens retain the early attachments to adult stage. The first publication record of it goes back to 1705 in Georg E. Rumphius's book "The Ambonese Curiosity Cabinet"; this was pre-Linneaus days and Linneaus described it formally in 1764. Although at least one of Linneaus' cited figures was not of this species but a turbinid, he did supposedly have a specimen which is now in the University of Uppsala and enjoys lectotype status. It was rare until the early 20th Century but today it is considered not uncommon, although the spines are fragile and good quality specimens are hard to come by. It is a deposit feeding omnivore mainly feeding on algae and foramniferan, and lives on sandy to muddy bottoms of moderate depths around -20~200m. Its distribution range is very wide throughout the Indo-West Pacific region, ranging from South Africa to Indonesia to Taiwan. Specimens from Vietnam are famous for being large with dense and long spines. Originally described as a subspecies of S. solaris, S. paucispinosa Kosuge & Nomoto, 1972 was given to population from South Africa and adjacent waters, which usually has less spines per whorl (13~15) and coarser, stronger sculpture. This is now considered to be a separate species in its own right. Typical shell length around 100mm including spines, extremely large specimens may exceed 135mm.

Spondylus gaederopus Linnaeus, 1758 <br />
SPONDYLIDAE<br />
-15m, Dived, Attached to stone, Kythnos Island, Greece, 62.2mm, F+, 2014/xi<br />
The "European Thorny Oyster" is a beautifully ornamented spondylid native to the Mediterranean Sea, Black Sea, and the adjascent northeastern Atlantic to northwest Africa. As is the norm with spondylids it lives a sessile life with left valve cemented to a hard substrate, and is a filter-feeding bivalve found from very shallow subtidal waters down to about -40m deep. An extremely variable species especially in spine development, the specimen shown has rather long and dense spines. The colouration also varies a little but typically the right valve is reddish brown to purple while the left valve is white. Although a common species most specimens are worn or with poorly developed spines; spectacular specimens are uncommon. It has been used in Europe for ornament making since more than 5000 years ago, as is evident from excavated specimens in burial sites such as Varna Necropolis, Bulgaria. Typical shell length including spines around 80mm, very large specimens may exceed 120mm.

Oenopota ogasawarana Okutani, Fujikura & Sasaki, 1993 <br />
MANGELIIDAE<br />
-399m, Daikoku Volcano Hydrothermal Vent Field, Mariana Arc, Northern Mariana Islands, 23.7mm, F++<br />
Oenopota ogasawarana is a mangeliid "turrid" endemic to hydrothermal vent fields of Kaikata Seamount, Daikoku Volcano, and Daini-Kasuga Seamount of the Izu-Bonin-Mariana Arc; the distribution range stretching across the border between Japan and Northern Mariana Islands (USA). These vent fields are rather shallow in depth ranging between -350~450m, and this species is only known from sandy to muddy bottoms around active vents. Although common where it is found the distribution is extremely limited in area and thus it is virtually impossible to obtain. Genetic studies have revealed high connectivity and gene exchange between its three populations which are up to 600km apart, they appear to do this through by having planktotrophic larvae which are carried by vent plumes for a long time and distance. Its feeding mechanisms are not known but is most likely a scavenger or predator of other vent organisms. A layer of thin greenish brown periostracum covers the entire shell, the apex is always corroded. Typical shell length around 20mm, giant specimens may exceed 30mm.

Clinopegma magnum (Dall, 1895) f. aequapaceum Tiba, 1981 <br />
BUCCINIDAE<br />
-400~600m, Off southeast Nemuro, Hokkaido, Japan, 97.5mm, F++, 2013/vii<br />
Known from Hokkaido, Japan to Sakhalin Island, Clinopegma magnum f. aequapaceum is a rather rare and perhaps the most attractive form of the "Magna Whelk". C. magnum is itself very widely distributed from Hokkaido, Japan to Aleutian Islands and is extremely variable. It may be fusiform or stout, and the number of spiral cord vary in general from a single strong subshoulder keel to more than ten; many names have been given to its various forms. Form aequapaceum represents a tall-spired variety with very strong cords; similar to C. magnum f. unicum (Pilsbry, 1905) but with more numerous and stronger cords below the sub-shoulder keel. C. m. f. unicum is often regarded as a Hokkaido to Sea of Okhotsk subspecies of C. magnum. It is a carnivorous / scavenging gastropod inhabiting sandy to muddy bottoms of rather deep water around -200~600m in depth. Typical shell length around 80mm, very large specimens may exceed 110mm.

Angaria formosa (Reeve, 1843) <br />
ANGARIIDAE<br />
-10~25m, Olango Island, Central Visayas, Philippines, 31.0mm, F++<br />
The "Taiwanese Delphinula" is a very attractive angariid ranging from Japan to Taiwan to Philippines to Vietnam to Malaysia. An extremely variable species in both form and colouration, especially with regards to spine formation. The most characteristic form has very wide and irregular downward-pointing spines like the depicted specimen resulting in dramatic shape as there may be as little as three spines covering the entire whorl. It is however also capable of producing regularly interspaced upward-pointing spines with variable lengths like most angariids, almost unbelievable that these are all forms of one single species. Regarding colouration, it often carry distinctive bands of red and white but may also be green and red or uniformly red; even golden specimens have been reported. It is often confused with Angaria nodosa (Reeve, 1843), another irregular and variable species, but may be distinguished by the sculpture. A. formosa has only very fine spiral cords while A. nodosa has generally stronger and wider cords; the cords of A. nodosa also almost always carry some dark pigments resulting in dark dotted lines running across the whole shell including umbilical region, this is not the case in vast majority of A. formosa. An algae-grazing gastropod inhabiting hard substrata of shallow water around -5~35m in depth, it is a rather uncommon species. Typical shell length around 40mm, very large specimens may exceed 60mm.

Homalocantha vicdani D'Attilio & Kosuge, 1989<br />
MURICIDAE<br />
-100m (-350ft), From 'snag nets', Off Bohol, Central Visayas, Philippines, 28.2mm, F++<br />
The "Victor Dan's Murex" is an intricately scabrous Homalocantha endemic to the Philippines. It is a member of the Homalocantha scorpio (Linnaeus, 1758) complex in the Philippines which comprises of several very closely related species, the others being H. pisori D'Attilio & Kosuge, 1989, H. dondani D'Attilio & Kosuge, 1989, as well as the recently described H. granpoderi Merle & Garrigues, 2011 and H. ninae Merle & Garrigues, 2011. A carnivorous and predatory gastropod inhabiting a rather wide bathymetric range from -20~150m, it is a rather rare species best known from Palawan to Visayas. Most specimens identified as H. vicdani are juveniles around 20mm in shell length, heavily scabrous and yellowish to reddish brown in colouration; these are very similar to and difficult to separate from H. pisori and H. dondani. Specimens supposed to be adult H. vicdani are extremely similar to H. scorpio. In fact this is true with all species in the complex and given H. scoprio is an extremely variable species, many if not all other currently recognised species in the complex are likely to be forms of H. scorpio. Typical shell length is only around 25mm as most are juveniles, adult specimens may exceed 55mm.

Spondylus imperialis Chenu, 1844<br />
SPONDYLIDAE<br />
Burias Island, Masbate, Philippines, 123.4mm, F++<br />
The "Imperial Thorny Oyster" is a splendidly spinous spondylid widely distributed in the Indo-West Pacific, ranging from India to South China Sea to Taiwan to Philippines. Typically uniform white in colouration (umbo is often pink), spines very long spines especially in young specimens; larger specimens often have shorter spines in proportion to the shell. It is in fact a very variable species and in some specimens the pink colouration persists and the whole shell may be tinged in pink. The depicted specimen is an uncommon form with very well-developed fine spines and pink hue persisting to adult size. Generally a common species, it is a filter-feeding bivalve normally found on shell debris and dead corals of shallow to moderate depths between -10~100m. Typical shell length including spines around 90mm, very large specimens may exceed 150mm. Some large specimens, especially the depicted form, are very similar to S. victoriae Sowerby II, 1860 (better known as S. wrightianus Crosse, 1872) from Australia; but S. victoriae has five to seven minor interstice ribs each carrying one row of smaller spines between the principal ribs compared to three minor interstice ribs in S. imperialis each carrying three rows of smaller spines, one from the centre and weaker ones from either side. S. victoriae also usually has much thicker and stronger spines on the principal ribs in the early growth stage.

Astralium tentorium (Thiele, 1930) <br />
TURBINIDAE<br />
Low tide, On rocks, Shark Bay, Western Australia, Australia, 35.8mm, F++<br />
Astralium tentorium is one of a few outstanding turbinids that produce vivid blue opercula. The colouration of its operculum is actually quite variable, ranging from blue to a dark purple and even blue ones often carry a tinge of purple near the nucleus. An algae-grazing gastropod inhabiting low tide zone of intertidal areas and shallow subtidal waters to about -5m, it is often found on or under rocks. Endemic to Western Australia and although a locally common shell, it is uncommon in the international shell trade market. The dorsum is generally rough and eroded, but the base is brilliant yellow in colouration with delicate squamose sculpture. Typical shell length around 40mm, very large specimens may exceed 50mm.

Turbo lamniferus Reeve, 1848<br />
TURBINIDAE<br />
Low tide, Regnard Bay, Western Australia, Australia, 44.5mm, F++<br />
The "Squamose Turban" is a medium-sized turbinid elaborately ornamented with dense wavy lamellae ranging from Western Australia to Queensland, Australia to New Guinea. It was for a long time widely known as Turbo squamosus Gray, 1847, hence the vernacular name. Although actually published a year prior to T. lamniferus Reeve, 1848, T. squamosus Gray, 1847 is unfortunately a junior homonym of the same name by Röding, 1798 (which is itself a synonym of Turbo bruneus (Röding, 1798)) and therefore not available. It is a locally common algae grazing gastropod inhabiting intertidal zone to very shallow water down to about -5m, often found on rocks or other hard substrata. Individuals are quite variable in the strength of lamellae, but are otherwise little-varied. Typical shell length around 40mm, very large specimens may exceed 55mm.

Lithopoma tectum (Lightfoot, 1786) f. olfersii (Philippi, 1846)<br />
TURBINIDAE<br />
Intertidal, On reefs, Salvador, Bahia State, Brazil, 40.0mm, F+, 1995/x<br />
The "Olfer's Star" is a Brazil endemic form of the "Imbricate Star" which ranges widely from Florida, USA to Brazil with a distribution centre in the Caribbean Sea. Traditionally, L. olfersii has been the name applied to specimens from Brazil as a separate species to L. tectum or a subspecies of it (ie. L. tectum olfersii) but there is no real difference in the shell and operculum between the two except the Brazilian specimens tend to be less elaborate in sculpture and often have taller shells. These differences are not consistent across the population and as L. tectum is extremely variable L. olfersii is currently best treated as a regional form of L. tectum, as L. tectum f. olfersii. A common algae-grazing gastropod, it inhabits rocky bottoms of intertidal to very shallow subtidal water less than -5m in depth. Typical shell length around 40mm, giant specimens may exceed 55mm.

Bolma modesta (Reeve, 1843) <br />
TURBINIDAE<br />
-50m, By lobster gillnet, Sakai, Minabe-Cho, Wakayama Prefecture, Japan, 58.3mm, F+/F++<br />
The "Modest Bolma" is an elaborately ornamented turbinid ranging from Honshu, Japan to Taiwan to East China Sea. The dorsum varies from pinkish to purple in colouration and carries two rows of strong spines as well as many rows of beaded cords; there is another row of moderate spines on the base. Spine development vary greatly among individuals, the depicted specimen has rather strong spines. The parietal callus is yellowish brown to golden and is rather widespead. A common grazing and detritus-ingesting gastropod inhabiting rocky to gravelly bottoms, it lives in depths ranging from -20~150m which is shallow for a Bolma. Typical shell length around 45mm, giant specimens may exceed 60mm.

Astralium stellare (Gmelin, 1791) <br />
TURBINIDAE<br />
Low tide, On outer reef, Shoal Point, Queensland, Australia, 38mm, F++<br />
The "Blue-Mouthed Star" is a remarkable turbinid with a striking sky blue columellar and operculum. It is one of the most celebrated blue shells, as true blue is rare in the shells of marine gastropods. Although usually a vivid blue, the operculum may sometimes carry a purplish hue. A locally common algae-grazing gastropod, it inhabits low tide zone of intertidal waters down to very shallow depths of around -5m. Geographically it is best known from Australia where is ranges from Queensland to Western Australia but is supposed to have a wider distribution in the Indo-West Pacific. Individuals vary greatly in development of varices, some specimens have very strong spine-like varices while others have modest nodule-like development. Often a very rough shell, it is not easy to find a quality specimen. Typical shell length around 35mm, very large specimens may exceed 50mm.

Astralium rotularium (Lamarck, 1822) <br />
TURBINIDAE<br />
Low tide, Under rocks on reef, Cape Leveque, Kimberley, Western Australia, Australia, 36.3mm, F++, 2014<br />
The "Rotary Star" is an intricately sculptured turbinid endemic to western and northwestern Australia. It is a common algae grazing gastropod inhabiting very shallow water from low tide zone of intertidal waters down to about -5m, often found under rocks or other hard substrates when not foraging. Although specimens are often dull white throughout, many carry a reddish tinge especially between spines of the earlier whorls. The varices vary somewhat in frequency among individuals, and are sometimes webbed. Typical shell length around 30mm, extremely large specimens may exceed 45mm.

Astralium provisorium (Schepman, 1903) <br />
TURBINIDAE<br />
-10~15m, On coral rubble, Olango Island, Central Visayas, Philippines, 19.7mm, F++<br />
Astralium provisorium is a moderate-sized and tall-spired turbinid endemic to the Philippines. Its range was originally considered to be restricted to the Sulu Archipelago, but a population was found around Olango Island and subsequently described as Astralium roseobasis Kreipl & Dekker, 2003. A. roseobasis is now considered a synonym of A. provisorium, extending its range to the Visayas; specimens are also known from localities inbetween such as near Bohol Island. The synonymisation took some time to confirm, partly because the holotype of A. roseobasis is in very poor shape. Presumably a grazing herbivore feeding on algae, it is usually found in shallow water around -10~50m and is somewhat uncommon. The overall form is little-varied but it is extremely variable in colouration from brown to yellow to pink to red, often very brightly coloured like the superb specimen depicted. Typical shell length around 20mm, very large specimens may exceed 25mm.

Guildfordia superba Poppe, Tagaro & Dekker, 2005 <br />
TURBINIDAE<br />
-100~200m, By tangle net, Tinina, Balut Island, Davao, Philippines, 89.4mm, F+/F++, 2014/viii<br />
The "Superb Star Turban" is a very beautiful turbinid recently described from Philippines where it is endemic to, and is best known from Davao Region, Mindanao. It is most similar to Guildfordia yoka Jousseaume, 1888, especially the golden deep-water form, but differs significantly in lacking most sculpture on the dorsum except one or two weak rows of pustules adjacent to the suture. The dorsum is thus rather glossy and is often decorated with patterns in the form of brown lines. The shell itself is large for the genus and its spines are proportionally shorter than G. yoka. It is presumed to be a bottom grazing / detritus ingesting gastropod and inhabits sandy to gravelly to muddy bottoms of rather deep water around -100~300m. It was considered rare for a few years since its original description but now it is being brought up more often by deep-water tangle nets and perhaps best described as locally uncommon. Typical shell length including spines around 75mm, very large specimens may exceed 90mm.

Cochlespira pulchella (Schepman, 1913) <br />
COCHLESPIRIDAE<br />
Dredged by local fisherman, In coral rubble, Off Aliguay Island, Mindanao, Philippines, 26.7mm, F++, early 2014<br />
The "Star Turrid" is an elegant cochlespirid 'turrid' with a strongly keeled scalariform spire and prolonged siphonal canal. A carnivorous and predatory gastropod inhabiting sandy to rubbly bottoms of rather deep water around -50~300m, it is primarily vermivorous and is somewhat uncommon. The overall geographic range is considered to be from Boso Peninsula, Japan to East China Sea to Philippines to Indonesia. Although the overall form is usually stable, the shoulder spines vary greatly in formation and some forms were described as distinct species but now considered to be synonyms; for example C. fossata Powell, 1969 and C. semipolita Powell, 1969. C. p. pulcherrissima (Kuroda, 1959) often has spines pointing sideways and is sometimes regarded as a northern subspecies ranging from Japan to East China Sea but its true status is not clear, may be a synonym but also sometimes considered a separate species. Typical shell length around 25mm, very large specimens may exceed 35mm.

Cylindrus gloriamaris (Chemnitz, 1777) <br />
CONIDAE<br />
-180~250m, By tangle net, Cebu Island, Philippines, 86.3mm, F++, 2008/xi<br />
The "Glory-of-the-Sea" is certainly the greatest historical rarity of all molluscs throughout the history of shell collecting. This distinguished cone with beautiful tent patterns was the most desirable and an exceptionally rare shell of for about two hundred years since the first specimen arrived in the western world as early as 1757. S. Peter Dance, who selected it as one of four greatest rarities in "Shell Collecting: An Illustrated History" (1966) and one of his 50 "Rare Shells" (1969), wrote: "some rare shells are well known; a few are famous; one, and one only, has become legendary"; "to see one was a priviledge, to hold one an honour, to own one a triumph". The handful of early specimens were all unlocalised but its true provenance was revealed by Hugh Cuming when he discovered two in the Philippines in 1836, but none were found after his visit and many considered it extinct; until 1957 when a living population was re-discovered once again in the Philippines. By 1960s many more had turned up from western Pacific and today it is only somewhat uncommon, many being brought up by deep-water tangle nets in the Philippines. Its distribution range is now known to be rather wide, ranging from the Philippines to Indonesia to Fiji to Samoa. Although it is found across a wide bathymetric range, -10~300m, most specimens are obtained from depths greater than -100m which certainly contributed to its initial scarcity. A predatory gastropod capable of injecting toxin using a dart-like radula like other conids, it inhabits sandy to muddy bottoms and is molluscivorous. The pattern is very variable and the shell is rather prone to growth lines. Specimens showing strong blue hues are known as well as a golden form. Typical shell length around 100mm, extremely large specimens may exceed even 170mm. Although much of its illustrous rarity has faded through the re-discovery, its fame and glory shall not; and it will always remain a must in any serious collection for as long as the history of shell collecting continues.

Tritogonia verrucosa (Rafinesque, 1820)<br />
UNIONIDAE<br />
Marais des Cignes River, Ottawa, Franklin County, Kansas, USA, 102.1mm, F+, Coll. 1994<br />
The "Pistolgrip" or "Buckhorn" is a large and thick unionid freshwater mussel endemic to USA and is wide-spread across the eastern half of the country. It is a filter-feeding burrower and inhabit sand, gravel, or mud bottoms of medium to large rivers down to depths of around -20m. It exhibits unioid's characteristic reproduction cycle of females brooding fertilised eggs until hatched and then release these larvae (the glochidia); which are obligate parasites attaching on fish gills or fins until dropping off to become sedentary mussels. It spawns in spring and releases glochidia in summer (ie. tachytictic), the host fishes of its glochidia are usually catfishes such as the "yellow bullhead" Ameiurus natalis (Lesueur, 1819) and the "flathead catfish" Pylodictis olivaris (Rafinesque, 1818). Rather uncommon throughout its range, it is threatened in some states such as Virginia and Wisconsin from habitat degredation like many other worldwide unionids. The shell is sexually dimorphic with the posterior part of shell compressed and elongate in females (depicted) and much truncated in males. The periostracum is lighter brown in juveniles and becoming darker towards black as the mussel grows older. Typical shell length around 120mm, very large specimens may exceed 160mm.

Tiphobia horei Smith, 1880<br />
PALUDOMIDAE<br />
-20m, Trawled on sand, Lake Tanganyika, Tanzania, 38.7mm, F++<br />
Ornamented with numerous pronounced elongate shoulder spines the "Hore's Tiphobia" is one of the most iconic and coveted freshwater gastropods world-wide, and exceptionally resembles some marine species such as muricids or genus Thalassocyon of Ficidae. It is a well-known endemic of the ancient Lake Tanganyika, the largest freshwater lake of Africa and second largest in the world, bordering Tanzania, Congo, Burundi, and Zambia. Lake Tanganyika is renowned for being a biodiversity hotspot and hosting many endemic species, most famously more than 250 species of cichlid fish but also more than 50 species of mollusc. An omnivorous epifaunal grazer feeding on deposits, it locally common througout the lake on sandy to muddy bottoms from very shallow waters down to -150m deep although generally found deeper than -50m and records exist for depth exceeding -300m. It is ovoviviparous meaning it gives birth to live young; eggs are retained within a uterine brood pouch until hatched. Live specimens are covered in a rather thick layer of brown periostracum. It is very variable in spine formation and somewhat in spire height. Typical shell length around 40mm, very large specimens may exceed 50mm. It was named in honour of the British Reverend Captain Edward Coode Hore who first discovered it among many other freshwater species during his visit to Tanzania during the late 1800s.

Thiara scabra (Müller, 1774) <br />
THIARIDAE<br />
On mangrove plant, Pelabuhan Ratu, Sukabumi Regency, West Java, Indonesia, 23.6mm, F++, 1980s<br />
The "Spiky Trumpet Snail" is a freshwater gastropod widely ranging from Amami Islands, Japan to Indonesia to Yemen. A popular snail for aquarists, it is often seen kept and bred in freshwater aquariums around the world and has been aritificially introduced to many countries in the southern Pacific such as New Caledonia and Solomon Islands. There is some uncertainty regarding wherther the African populations are the same species as the Asian ones, and if they have been artificially introduced or not. Although most specimens carry numerous attractive long spines, it is in fact extremely variable in spine growth and strength of sculpture; some specimens lack spines entirely. It is also variable in shell height / width ratio, the depicted specimen is rather fusiform. The ostracum may be white to brown and may carry patterns consisting of dark straight or zigzac lines; overlaid with a thick layer of dark brown to black periostracum. As is the norm for freshwater snails, the apex is usually corroded away in adults. It is a common algae-grazing herbivorous gastropod inhabiting freshwater streams as well as some brackish estuaries. Typical shell length around 25mm, very large specimens may exceed 35mm.

Bolinus cornutus (Linnaeus, 1758) <br />
MURICIDAE<br />
Dakar, Senegal, 132.0mm, F/F+<br />
The "African Horned Murex" is a large club-shaped muricid native to western Africa, ranging from Mauritania to Angola (including Cape Verde). Each whorl bears seven spinous varices, each usually bearing two strong spines near the shoulder and many weaker ones towards the siphonal canal. Individuals vary greatly in spine length and curvedness; irregularity in spine growth is not uncommon. The colouration is also very variable and can vary from off-white to almost black. The club-shaped shell and long varices make it closely resemble members of the genus Tudivasum in Turbinellidae, although the protoconch of Tudivasum is bulbous and very different. Like its only congener B. brandaris (Linnaeus, 1758) which was used to produce the ancient Tyrian purple dye, the mucus of B. cornutus also turns purple upon contact with air and may be used to produce purple dye. A carnivorous and predatory gastropod, it inhabits mostly sandy to muddy bottoms of moderately shallow waters around -5~80m deep and is not uncommon throughout its range. Typical shell length around 150mm, extremely large examples may exceed 200mm.

Scutellastra longicosta (Lamarck, 1819) <br />
PATELLIDAE<br />
Low-tide, On rocks, False Bay, Cape Peninsula, South Africa, 75.2mm, F++<br />
The "Long-Ribbed Limpet" is a spectacular limpet characterised by long spine-like digits displayed in a "star-burst" pattern, native to South Africa and southern Mozambique. The digit development is extremely variable and so is sculpture strength; many specimens have short and subdivided digits as opposed to the long-digit form depicted here. A common grazing gastropod inhabiting mid to low tide zones of intertidal rocky shores, it is known to exhibit territorial behaviour as part of the mutualistic relationship with the brown algae Ralfsia verrucosa Areschoug, 1845. R. verrucosa is the limpet's preferred food species and the limpet clears away new settlement space for R. verrucosa by grazing away existing vegetation. After R. verrucosa establishes in the new territory, the limpet fascilitates its growth by fertilisation using mucus and faeces as well as prying off intruding organisms from the territory. The algae therefore gains new habitat protected by the limpets and the limpets in return gets a constant supply of their favourite food by 'farming'. The limpet's long digits are considered to have evolved to increase efficiency in prying off intruders as well as to increase surface area of attachment to the rock. Typical shell length around 60mm, very large specimens may exceed 90mm.

Paludomus loricatus Reeve, 1847<br />
PALUDOMIDAE<br />
Colombo, Sri Lanka, 26.4mm, F++, 1970s<br />
Paludomus loricatus is a prickly and attractive freshwater snail endemic to India and Sri Lanka. The fine-scale distribution is not well-understood especially outside Sri Lanka as it is recorded from a few disjunct localities in India (e.g., Assam and Arunachal Pradesh) but not between them. This is likely to be a result of either poor sampling efforts or mis-identificaton with other Paludomus species. Also, although more than fifty species of Paludomus have been described from the region, freshwater snails may vary considerably in morphology depending on environmental factors many are likely to be synonyms of P. loricatus. It is a herbivorous algae-grazing gastropod inhabiting slightly acidic and slow-flowing mountain streams, and is locally common (especially in Sri Lanka where it is one of the most common Paludomus species). Somewhat variable in spire height, many carry striking pattern of zig-zag lines but is usually concealed under the rather thick, brown periostracum. It is a popular algae-grazer species for freshwater aquarists and are kept and bred in aquaria around the globe outside its natural range. Typical shell length around 30mm, giant specimens may exceed 40mm.

Atalacmea fragilis (Sowerby I, 1823) <br />
LOTTIIDAE<br />
Slipper Island, Off Coromandel Peninsula, North Island, New Zealand, 10.4mm, F++, 1952<br />
The "Blue-Ringed Limpet" must be one of the most striking of all lottids. The shell is characterised by a pattern consisting of radial green to brown lines with the interline spacing filled by a brilliant turquoise or blue. A algae-grazing gastropod, it inhabits rocky surfaces of intertidal to very shallow water less than -10m deep and is endemic to the North, South, and Stewart islands of New Zealand. Although locally not uncommon, it is somewhat rarely seen on the shell market probably due to its small size and difficulty in obtaining quality specimens as the shell is extremely fragile as the specific epithet suggests. Typical shell length arond 15mm and very large specimens may exceed 20mm. It can only be confused with its only congener Atalacmea multilinea Powell, 1934 endemic to the South Island of New Zealand, which has a similar pattern but with interline spaces filled by off-white to light brown instead of torquoise; the greenish lines are also generally thinner. A. multilinea is also much smaller than A. fragilis, averaging at about 7mm and maxes out around 12mm.

Dicathais orbita (Gmelin, 1791) <br />
MURICIDAE<br />
Cornwallis Beach, Manukau Harbour, Auckland, New Zealand, 70.2mm, F++, 2000/xii<br />
The "Common Cartrut" or "Cartwheel Purple" is a large rock shell ranging from Australia (Queensland to Western Australia, including Lord Howe Island and Tasmania) to New Zealand. It is a common to abundant carnivorous gastropod across the range and inhabits rock surfaces of intertidal to very shallow water less than -10m deep. Mainly a predator preying on other molluscs such as Lunella torquata (Gmelin, 1791) and Septifer bilocularis (Linnaeus, 1758) but may also scavenge; it forages up the shore during high tide and retreats to rock crevices during low tide. It is currently the only species in genus Dicathais but is extremely variable in sculpture / shape and different forms were once considered to be separate species. For example specimens from southern Australia is generally reduced in sculpture and has been named Dicathais textilosa (Lamarck, 1822); nodulous specimens from western Australia lacking strong radial ribs were given the name D. aegrota (Reeve 1846). The variation is known to be attributable to a mixed effect of temperature, diet, substrate, and exposure to wave action; a moderately strongly sculptured specimen is depicted here. The thick, heavy shell is usually white to grey but juveniles are often brown with thinner shells. Typical shell length around 60mm, extremely large specimens are known to reach even 120mm.

Perisserosa guttata (Gmelin, 1791) <br />
CYPRAEIDAE<br />
Deep water by tangle net, Balut Island, Philippines, 65.7mm, F+++, Col. ii/2004<br />
The "Great Spotted Cowrie" is a lovely classic rarity among cypraeids characterised by circular bright spots on the dorsum and long tooth on the base extending to the dorsum as marginal lines. One of S. Peter Dance's fifty "Rare Shells" (1969), only sixteen were known by 1963 according to a list of known specimens published then by Woodward and it was exceedingly rare until the late 1900s. Today it is known to be a widely distributed species ranging from Maldives to Japan to Philippines to Queensland, Australia; it is very variable and several forms / subspecies names are currently being used. The nomimal subspecies occurs from Philippines to Queensland and is uncommon, best known from moderate depths around -25~100m in the Philippines where specimens with clear large spots are taken by diving or tangle netting. The form azumai (Schilder, 1960) is a northern form of guttata with smaller indistinct spotting and often lacking the labral blotch known from Japan and East China Sea; in recent years the Chinese trawlers are producing a huge quantity of this form from the East China Sea making it very common and inexpensive, but most specimens are quite poor. The form bicallosa (Raybaudi, 1985) refers to an angular form with well-developed white callous on both sides best known from Philippines. It is extremely rare in Queensland, its southern limit, and the specimens from here (usually deeper water around -150~300m) may represent a real subspecies; although not formally named these are often referred to as "queenslandica" on the market. The only widely accepted subspecies except the nominal guttata guttata is the uncommon Indian Ocean subspecies guttata surinensis (Raybaudi, 1978) from deeper waters (-100~300m) of Maldives to Thailand; characterised by an depressed oval shape, fine spots, darker alnd larger basal blotches, and much longer marginal lines. It is an omnivorous gastropod often inhabiting crevices of rocky walls. Extremely variable in size, the typical shell length is around 55mm but specimens smaller than 35mm and larger than 85mm are known to exist; specimens less than 45mm or over 70mm are rather rare. It is still one of the most sought-after cowries today, giant dark specimens with large well-defined spots are perhaps the most coveted although an ideal specimen is still very difficult to obtain.

Pterynotus elongatus (Lightfoot, 1786) <br />
MURICIDAE<br />
In tangle net by local fisherman, Mactan Island, Cebu, Philippines, 72.8mm, F+/F++, early 2014<br />
The "Club Murex" is an elegantly and curiously shaped muricid distributed very widely across the entire Indo-West Pacific region ranging from eastern Africa to Hawaii, USA including the Red Sea and best known from the Philippines. Although a common species today, it was historically a famous rarity and is one of S. Peter Dance's 50 "Rare Shells" (1969). Since around 1767 when it first appeared in the western world it has been very rare; until mid to late 1900s when divers from the Philippines and other countries began to recover it in good quantities. A carnivorous gastropod inhabiting rocky to sandy bottoms of around -5~150m deep, it was rare despite the relatively shallow depths of -10~40m where it is most often found partly because live specimens are well concealed by marine overgrowth. Often found on hard corals with complex structures, making it even more difficult to locate. Both scientific and vernacular name refers to its spire which is usually slender-looking due to the fragile varices are damaged on the earlier whorls. Uncommonly specimens with intact varices on earlier whorls are found and these are truly wonderous. Majority of specimens are pure white in colouration but the colouration is actually variable from white to yellow to orange to brown and even violet. Typical shell length around 70mm, extremely large specimens are known to exceed 100mm.

Leporicypraea valentia (Perry, 1811) <br />
CYPRAEIDAE<br />
-30~50m, Dived, Camotes Islands, Camotes Sea, Philippines, 88.2mm, GEM-<br />
The "Prince Cowrie" is a very famous classic rarity among cypraeids with a distribution from the Philippines to Melanesia to the northernmost Australia, although by far best known from the Philippines. It is one of S. Peter Dance's 50 "Rare Shells" (1969) and only half a dozen specimens were known when the book was published. The first specimen known in the western world was obtained by Lord Valentia (ie. George Annesley) from George Humphrey and eventually became the holotype when George Perry described the species in 1811 using the same specimen and dedicated the specific epithet to its owner. This specimen is currently housed in the Natural History Museum, London. There have been some controversy over its provenance in the early years, many thought it was an Indian Ocean shell and it was not until after the mid-1900s that its Pacific origin was widely accepted. This was because it was 'long-lost': no specimens were found for many decades, until Phillip Clover finally obtained a reliably localised specimen in 1967 (collected in the year before) from New Britain. This re-discovery was reported by S. Peter Dance in the Hawaiian Shell News (June 1968). It remained exceptionally rare until around and after 1980s when specimens began to turn up from the Philippines with the widespread of SCUBA diving and the advent of tangle nets targeting molluscs. Although it is only moderately rare and much readily obtainable nowadays it remains one of the most desirable cowries of all. It is a omnivorous gastropod inhabiting caves and crevices of rocky walls in moderate depths around -15~80m, the typical shell length is around 80mm while extremely large specimens may exceed 100mm. It is a relatively little-varied species and is easily distinguished from other cowries. It is worth noting that the Philippine Fisheries administrative order 208 (effective 2001) forbids collecting and exporting of L. valentia; although the order appears to be poorly enforced and many specimens continue to be traded every year.

Pedum spondyloideum (Gmelin, 1791) <br />
PECTINIDAE<br />
By local hookah diver, Cordova, Cebu, Philippines, 83.3mm, F+, early 2014<br />
The "Coral Scallop" is a strange and unique pectenid that strongly resemble spondylids (hence the binomial name), and is the only species in genus Pedum. It is a common obligate scleractinian stony coral associate widely distributed throughout the entire Indo-Pacific region and lives embedded in live coral skeleton to which it is attached using byssus threads. It uses a variety of coral hosts such as genera Montipora, Porites, and Pavona in shallow water ranging between -2~20m; massive Porites appear to be the favourite. The shell is mostly surrounded by coral skeleton in adults as the coral would have grown and expanded since it settled. It has been suggested that this scallop-coral relationship may be mutualistic with the scallop providing coral enhanced water circulation for feeding and generating water jets to repel coral predator while the coral provides structural support and protection to the scallop. Both valves are usually white, sometimes carrying brown blotches or streaks; black specimens are also known but rarer. The shape is very variable. Typical shell length around 60mm, gigantic specimens may exceed 100mm.

Bathymodiolus elongatus von Cosel, Métivier & Hashimoto, 1994 <br />
MYTILIDAE<br />
-2750m, Mussel Valley Hydrothermal Vent Field, North Fiji Basin, 118.8mm, F++, 1980s<br />
Bathymodiolus elongatus is a splendid deep-sea mussel endemic to hydrothermal vent fields of the North Fiji Back-Arc Basin of western Pacific Ocean. Typical of thioautotrophic bathymodiolins, it has a much enlarged gill housing chemoautotrophic sulphur-oxidising bacteria and derives most of the energy through them; although it is also capable of filter-feeding if necessary. The periostracum is glossy and chestnut brown in colouration, lightening towards the umbo. It co-occurs with another Bathymodiolus species, B. brevior Cosel, Métivier & Hashimoto, 1994 which has a much more stout shell; the name 'elongatus' is taken from the fact that it is the more elongate species of the two. The two species inhabit different parts of the vent field: B. elongatus is found in cooler diffuse flow sites and live in areas not exceeding 8.5 degrees Celsius in water temperature whereas B. brevior mostly inhabit areas close to black smoker chimneys where the water temperature is up to 18 degrees Celsius. Both species form large aggregations and are often covered in byssus plaques of other individuals in close proximity. The typical shell length of B. elongatus is around 100mm, although extremely large specimens may exceed 140mm.

Spirula spirula (Linnaeus, 1758) <br />
SPIRULIDAE<br />
On beach, Solomon Islands, 24.5mm, F++<br />
The "Ram's Horn Squid" is a very unique cephalopod with a loosely coiled chambered shell. It is a not a true squid (order Teuthida) but the only surving species of the order Spirulida; its shell is a true shell and is actually internalised like a true squid but is visible from the outside even in a live animal. It is considered to be the closest extant relative of the extinct belemnites (order Belemnitida), and is also closely related to extant cuttlefishes and squids. Like its distant cousin the nautiluses, it uses the chambered shell (around 25-37 chambers) as a buoyancy organ for vertical movement by controlling the gas / liquid ratio in the chambers using osmosis. A deep-sea carnivorous cephalopod distributed throughout the world's tropical oceans, it lives in water column around continental shelf down to great depths of -1000m and is most often seen around -200~700m although very occasionally also ventures into shallow water less than -20m deep. It exhibits diurnal vertical migration, rising to shallower depths for feeding at night and spends the day in the deep. Like many deep-sea cephalopods it is capable of bioluminescence from a photophore at the very posterior end between the fins, which emits a green light. Its radula is extremely reduced. The animal is very rarely seen but the shell is common and often washes up to beaches and shores, because after the animal dies the gas-filled shell floats to the sea surface and becomes pelagic. Typical shell length around 25mm, very large specimens may exceed 35mm. The animal is typically around 35mm in mantle length and 70mm in entire length.

Japelion pericochlion (Schrenk, 1863) <br />
BUCCINIDAE<br />
-200~250m, Trawled, Off Sōma, Fukushima Prefecture, Japan, 120.1mm, F+/F++, 2009/vi<br />
The "Peri Japelion" is a large cold-water buccinid endemic to Japan, ranging from Chiba Prefecture to Hokkaido and is best known from Fukushima Prefecture. It is a somewhat uncommon carnivorous / scavenging gastropod inhabiting muddy bottoms of rather deep water around -100~400m. A number of similar Japelion species are also found in Japan, most notably and commonly seen are J. hirasei (Pilsbry, 1901) and J. adelphicus (Dall, 1907). J. hirasei differs by having usually a broader subsutral platform and a much shorter anterior siphonal canal, and J. adelphicus differs by having no subsutral platform and only a raised keel. All three species are sometimes seen (J. pericochlion usually mixed-in with J. hirasei) in Japanese fish markets and are sold for food like many large cold-water buccinids in Japan. They are most commonly eaten raw as sashimi / sushi or steamed using Japanese sake. Typical shell length around 110mm, extremely large specimens may reach 150mm.

Hyriopsis bialata Simpson, 1900<br />
UNIONIDAE<br />
Yom River, Saerabhumi, Roi Et Province, Thailand, 85.6mm, F++, 2013/iii/07<br />
Hyriopsis bialata is a freshwater mussel with an extraordinary shape from a raised keel in the posterior half of the shell, which varies in extent greatly between individuals with some completely lacking it. It is native to southeast Asia from Thailand to Cambodia; and is a filter-feeding bivalve inhabiting sandy bottoms of river streams. It is an economically important species locally especially in Thailand, with the nacreous shell and pearl produced being used in various kinds of jewelry and ornament making and the meat being used for food or livestock feed. Although a common species, human-induced environmental degradation is causing population in Thailand to decline rapidly in the recent years. It is one of the most fecund (fast generation time, spawning throughout the year) unionids native to the area and aquaculture of this species exist in Thailand. Typical shell length around 80mm, extremely large specimens may approach even 130mm.

Nacella polaris (Hombron & Jacquinot, 1841) <br />
NACELLIDAE<br />
On rocks, King George Island, South Shetland Islands, Antarctica, 53.4mm, F, Coll. S. Maytía, 1992/iv/03<br />
The "South Polar Limpet" is a sub-Antarctic to Antarctic nacellid mainly distributed in the Scotia Sea but extends further to reach Bouvet Island. The name of this species has been intricately confusing. First described as Patella polaris Hombron & Jacquinot, 1841; it was known by this name for a long time until Powell in 1973 recognised that the name is a junior homonym of Patella polaris Röding, 1798. Powell replaced the name with Nacella concinna (Strebel, 1908), which was originally described as a deep water form; until Engl decided the name N. polaris is available afterall in his 2012 book 'Shells of Antarctica'. It is a algae-grazing herbivorous gastropod living attached on rocky surfaces from intertidal zone down to about -200m deep. The shallow water nominal form (shown here) has a rather elevated shell with weak to no ribbing as adults, whereas the deep water N. polaris f. concinna is much more flattened and usually carry strong radial ribs numbering 28-30. The nominal form is also generally larger with typical shell length around 40mm and up to 65mm, f. concinna averages at around 25mm but giants may exceed 50mm. Although it is locally a very common species it is uncommon on the shell market due to its remote distribution.

Eutrochatella tankervillii (Gray, 1824)<br />
HELICINIDAE<br />
Cockpit Country, Trelawny Parish, Jamaica, 23.6mm, F++<br />
The "Tankerville’s Trochatella" is a lovely helicinid landsnail endemic to Jamaica. It is a herbivorous / detritivorous gastropod grazing algae and other organic matters on rock surfaces where it lives. Highly sculptured for a Eutrochatella and usually with an attractive pattern which is variable among individuals. Rather large for the genus, its typical shell diameter is around 15mm with very large specimens growing to approach 25mm. An uncommon species, it is not frequently seen on the shell trade market due to its limited range. Helicinids are remarkable among landsnails as they evolved to live on land independently (and likely earlier) from better-known landsnail groups such as the pulmonates. They belong to the clade Neritimorpha and are in fact closely related to freshwater and marine nerites; they still carry a calcareous operculum.

Clithon coronatum Leach, 1815 <br />
NERITIDAE<br />
Mauritius, 28.5mm, F+, Very old collection<br />
The "Coronate Nerite" is a superb neritid with perhaps the longest spines of all species in the family. The spines number about four to six on each whorl and are mostly made of thick periostracum folded in a tube-like manner, and thus it is rather flexible in life and although the animal burrows under rocks or detritus the spines do not easily break. This species is confined to the Indian Ocean and supposedly endemic to the Mascarene Basin, best known from Mauritius and Réunion. Often seen placed in genus Theodoxus as T. coronatus (Leach, 1815) which refer to the same name. Although many records exist across the Indo-Pacific region extending to the Philippines and Polynesia, these are likely to be misidentifications with similar spined brackish congeners such as Clithon corona (Linnaeus, 1758) or C. recluzianus (Le Guillou, 1841). It is perhaps most confused with C. corona, a western Pacific species with a similar specific epithet but C. corona has shorter spines and is often highly patterned, with a lighter coloured operculum. C. coronatum generally lacks any colouration and is uniformly very dark reddish brown to black (although may have light/dark radial stripes), with a more pigmented operculum. The spines vary somewhat in length, very long spined ones such as the specimen shown here are often referred to as f. longispina (Récluz, 1841). An algae-grazing herbivorous gastropod inhabiting shallow brackish streams and waters, it is locally common but increasingly uncommon on the shell market due to its restricted distribution. Typical shell length around 25mm including spines, very large specimens may reach 40mm.

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