86 



Distribution : — /. perna bas a very wide range of distribution in the Indo-Pacific. 



In the "Siboga" collections it is represented by a very fine séries of shells from the Bay 

 of Kankamaraân, S. coast of Kangeang (St. i6), Anchorage off Labuan Pandan, Lombok 

 (St. 34), Sailus Ketjil, Paternoster Islands (St. 37), Bay of Badjo, West coast of Flores (St. 50), 

 Anchorage off Seba, Savu (St. 58), East side of Pajunga Island, Kwandang Bay (St. 115), 

 Taruna Bay, Great Sangir Island (St. 127), Anchorage off Kawio and Kamboling Islands 

 (St. 129), Anchorage off Beo, Karakelang Islands (St. 131), Sanana Bay, East coast of Sula Besi 

 (St. 193), Saleyer (St. 213) and (St. 225) near Lucipara Island. 



6. Isognomoti anomioides (Reeve). 



1858, Perna anomioides Reeve, Conch. Icon., XI, Perna, pi. III, fig. 11. 

 1860. Perna Anomioides Reeve, Elem. Conch., II, p. 66. 



1877. Isognomon [Perna) anomioides Pagenstecher, Zool. Ergebn. Reise Rothen Meer. Mollusk., 

 p. 32. 



1890. Perna anomioides Paetel, Cat. Conch. Samm., III, p. 206. 



1891. Perna anomioides Clessin in Martini-Chemn. Conch. -Cab. (N. F.), VIII (l), Malleacea, 



p. 31, pi. X, fig. I. 

 1897. Perna anomioides Sowerby, Mar. Shells S. Africa, Suppl., p. 27. 

 1903. Perna Anomioides Hidalgo, Cat. Filip., p. 368. 



191 1. Melina anomioides Lamy, Bull. Mus. d'Hist. Nat. Paris, XVII, p. 130. 

 1928. Pedalion anomioides Faustino, Summary Philippine Mar. Freshw. Mollusks, p. 24. 



The adult shell in this species is oblique, greatly elongated, somevvhat tongue-shaped, 

 but the young are more regular and almost circular in outline. The shell is thin and somewhat 

 transluscent, of a yellowish white colour, with the nacreous layer of a shining pearly colour. 

 The hinge-line is very short, and the umbonal area and the byssus gape are prominent. 



Distribution: — Reeve gives the habitat of /. anomioides as "California", but on the 

 type-tablet from the Cuming collection in the British Muséum (Nat. Hist.), London, the locality 

 is given as the Torres Straits. /. anomioides bas also been recorded from the Philippines, 

 Mauritius, S. Africa and the Red Sea, and appears to be widely distributed in the Indo-Pacific 

 Région and the Red Sea. 



The "Siboga" Expédition collected shells from the east side of Pajunga Island, Kwandang 

 Bay (St. 115) and Anchorage South of Lucipara Group (St. 225^=). 



7. Isogtiomon marsnpiale (Roding). 



1784. Varietas Marsupii Hiingarici equitis Chemnitz, Conch. -Cab., VII, p. 249, pi. LVIII, fig. 577. 

 1798. Isognomiim marsnpiale Roding, Mus. Boltenianum, p. 168. 

 1819. Perna marsupium Lamarck, Anim. sans Vertèb., VI, p. 141. 



1824. Perna marsupium Dubois, Epitome, p. 109. 



1825. Perna Marsupium Sowerby, Cat. Tankerville, p. 23. 



1842. Perna marsupium Sowerby, Conch. Man., p. 222, pi. IX, fig. 66. 



1843. P^^Jid Marsupium Hanley, Rec. Biv. Shells, p. 258. 



1845. Perna marsupium Catlow & Reeve, Conch. Nomencl., p. yj. 



1855. Perna marsupium Berge, Conchylienbuch, p. 88. 



1857. Isognomon marsupium Adams, H. & A., Gen. Rec. Moll., II, p. 527. 



1858. Perna marsupium Reeve, Conch. Icon., XI, Perna, pi. III, fig. 15. 

 1867. Perna marsupium Reeve, Elem. Conch., II, p. 66. 



