199 



i853- Amphidesma exarata Reeve, Conch. Icon., VIII, Ainpliidesnia, pi. I, fig. l. 



1856. Amphidesma exarata Adams, H. & A., Gen. Rec. Moll., II, p. 411. 



1860. Ampliidesma exarata Reeve, Elem. Conch., II, p. 138. 



1863. Ampliidesma exarata Tryon, Amer. Journ. Conch., IV, p. 120. 



1890. Amphidesma exarata Paetel, Cat. Conch. Samm., III, p. 63. 



1903. Semele exarata Hidalgo, Obras Malacol., II, p. 70. 



1905. Semele exarata Hidalgo, Cat. Filip., p. 264. 



1906. Semele exarata Hedley, Proc. Linn. Soc. N. S. Wales, XXXI, p. 466. 

 19 10. Semele exarata Hedley, Austral. Ass. Adv. Sci., XII, p. 350. 



191 3. Semele exarata Hedley, Proc. Linn. Soc. N. S. Wales, XXXVIII, p. 274, pi. XVII, 



figs- 34—37- 



1914. Semele exarata Lamy, Journ. Conchyliol., LXI, p. 343. 



1928. Semele exarata Faustino, Summary Philippine Mar. Freshw. Moll., p. 96. 



Semele exarata is easily distinguished by its oblong- ovate and somewhat oblique shell 

 and the sculpture consisting of concentric, thin ribs, somewhat recurved anteriorly and posteriorly. 



Distribution : — 5. exarata is known from the Australian waters and the Philippines. 



The "Siboga" Expédition collected only dead shells of this species in the Bay of Pidjot, 

 Lombok (St. 33), Anchorage near Seget, west entrance of Selee (Galewo) Strait (St. 163) and 

 Sulu. A young shell from the Anchorage off Djangkar, Java (St. 4) is probably to be referred 

 to this species. 



Genus Abra Lamarck. 



18 18. Abra Lamarck, Anim. sans Vertèb., V, p. 492. 



1843. Syndosmya Recluz, Rev. Zool. Soc, VI, pp. 292, 359. 



1852. Orixa Leach, Moll. Great Britain, p. 280. 



1856. lacra Adams, H. & A., Gen. Rec. Moll., II, p. 409. 



1887. Syndesmya and Orixa Fischer, P., Man. Conchyliol., pp. 1151, 1152. 



1900. Abra Dali, Trans. Wagner Free Inst. Sci. Philadelphia, III, p. 995. 



191 3. Syndesmya Lamy, Journ. Conchyliol., LXI, p. 268. 



1925. Abra Woodring, Miocène Mollusks from Bowden, Jamaica, Pelecypods etc., p. 179. 



The genus Abra was adopted by Lamarck from the manuscript name of Leach ^). The 

 type of the genus is Abra tenuis (Montagu). The genus is usually divided into two subgenera 

 Abra^ s. s.^ and lacra A. Adams. 



I. Abra maxima (Sowerby). 



1894. Syndesmya maxima Sowerby, Proc. Malacol. Soc. London, I, p. 40, pi. V, fig. 5. 



1894. Abra maxima Smith, Ann. Mag. Nat. Hist., (6), XIV, p. 169, pi. V, figs. 5 — 6. 



1895. Abra maxima Smith, Ann. Mag. Nat. Hist., (6) XVI, p. 10. 



1897. Abra maxima Smith, lUustr. Zool. R. I. M. S. "Investigator", Moll., pi. III, figs. 7, '/a. 



The shells collected by the "Siboga" Expédition agrée in every respect with the type and 

 other spécimens of the species from the Bay of Bengal and the Gulf of Oman collected by 

 R. L M. S. "Investigator". 



Distribution: — Abra maxima has been taken in the Bay of Bengal and the Gulf of 

 Oman. It is probably widely distributed in the Indian Océan. 



i) See Gray, J. E. — Ann. Mag. Nat. Hist., (i) XX, p. 272 (1847). 



