72 



M. {M.) elongatus is allied to M. {M.) philippinaruni Hanley, M. {M.) metcalfei Hanley 

 and M. {M.) arata Hanley, but is easily distinguished by its comparatively much elongated and 

 narrow shell, a moderately developed post-dorsal vving and rather feeble sculpture. 



Distribution : — M. iJM.) elo7igatîis has so far been recorded from the Moluccos, Aru 

 Islands, Penang and the Gulf of Siam. The locality Antilles, as noted by Clessin for the shell 

 in the Paetel collection, is certainly erroneous. 



The "Siboga" collection has two shells from St. i (Madura Strait, 7° 27'. 5 S., 11 3° 8^.5 E.), 

 and St. 320 (6° 5' S., ii4°7'E.). 



2. Modiolus [Modiolus) philippinarum (Hanley). (Plate II, figs. 25, 26). 



1843. Modiola Philippinarum Hanley, Rec. Biv. Shells, p. 235, pi. XXIV, fig. 26. 



1844. Modiola Philippinartiin Hanley, Proc. Zool. Soc. London, p. 15. 



1845. Modiola philippinarum Catlow & Reeve, Conch. Nomencl., p. 72. 

 1857. Modiola Philippinarum Reeve, Conch. Icon., X, Modiola, pi. I, fig. i. 

 1857. Perna Philippinarum Adams, H. & A., Gen. Rec. Moll., II, p. 517. 

 1870. Perna fulgida Mac Andrew, Ann. Mag. Nat. Hist., (4) VI, p. 448. 



1874. Modiola Philippinarum Tapparone-Canefri, Ann. Mus. Civ. Stor. Nat. Genova, VI, p. 566. 



1882. Perna Philippinarum de Rochebrune, Bull. Soc. Philomat. Paris, (7) V, p. 40. 



1886. Modiola fulgida [= philippinarum) Cooke, Ann. Mag. Nat. Hist., (5) XVIII, p. 140. 



1890. } Modiola Philippiana Paetel, Cat. Conch. Samm., III, p. 197. 



1896. Modiola P/iilippinarian Casto de Elera, Cat. Sist. Filip., p. 793. 



1899. Modiola philippinarum Melvill & Standen, Journ. Linn. Soc. London (Zool.), XXVII, p. 184. 



1905. Modiola philippinarum Hidalgo, Cat. Filip., p. 364. 



1906. Modiola philippinarum Smith, Ann. Mag. Nat. Hist., (7) XVIII, p. 254. 



1907. Alodiola philippinarum Melvill & Standen, Proc. Zool. Soc. London, p. 800. 



1909. Modiola Philippinarum Lynge, D. Kgl. Dansk. Vidensk. Selsk. Skr. Nat. -Math., (7) V, p. 132. 

 191 1. Modiola australis Pelseneer (nec Gray), "Siboga" Lamellibranches (Anat.), p. 117, pi. V, 



fig. 2. 

 1914. Modiola philippinarum Iredale, Proc. Zool. Soc. London, p. 667. 

 1919. Modiola Philippinarum Lamy, Bull. Mus. d'Hist. Nat. Paris, XXV, p. i 10. 



Modiolus [Modiolus] philippinar-iiin has often been confused with M. mistralis Gra)' from 

 North Australia, but there can be no question of the two species being distinct. The young 

 shells of the two species are rather difficult to separate but the adults of the two species can 

 be easily distinguished. M. [M.) pJiilippinarum is more inflated, has a well developed post-dorsal 

 wing and the posterior margin of the wing forms a broad arc with the nearly straight dorsal 

 margin, the umbones are much more prominent and more tumid, while the lines of sculpture 

 are more impressed. In M. australis the shells are, further, distinctly compressed and distorted, 

 somewhat behind the umbonal région. 



According to von Martens ^) M. rumphii of Philippi is a synonym of this species. 



Distribution : — M. {M.) philippinarum has a wide distribution in the Indo-Pacific and 

 the Red Sea. 



In the "Siboga" collection the species is represented by a fair séries of shells from 

 Anchorage off Pulu Sarassa, Postillon Islands (St. 43), Bay of Bima (St. 47), Bay of Badjo, west 

 coast of Flores (St. 50), Anchorage between Gisser Island and Ceram Laut (St. 172), Banda 



i) Martens, E. vox. — Rumphius Gedenkboek, Moll., p. 12g (1902). 



