205 



D. [L.) faba varies in colouration and forni to the same extent as D. (Z.) cuneata. 

 Romer's figures show the great variation of the species very well. 



Distribution: — D. (Z.) faba has a wide range in the Indo-Pacific Région. 



In the "Siboga" collection it is represented by a single shell collected in the Bay of 

 Labuan Tring, west coast of Lombok (St. 19). 



Family Mesodesmatidae. 

 Genus Mesodesma Deshayes. 



1830. Mesodesma Deshayes, Encyclopéd. Méthod., II, p. 442. 



1887. Mesodesma Fischer, P., Man. ConchylioL, p. 11 12. 



1895. Mesodesina Dali, Trans. Wagner Free Inst, Sci. Philadelphia, III, p. 911. 



1914. Mesodesma Lamy, Journ. ConchylioL, LXII, p. 14. 



Mesodesma s. s., with the génotype Mesodesma donacium (Lam.) is not represented in the 

 "Siboga" collection, but the subgenera Davila Gray ^) — génotype Davila polita Gray = 

 Mesodesma [Davila^ planum Hanley — and Atactodea Dali ^), génotype Mesodesma [Atactoded) 

 glabrata (Lam.) are represented by one species each. 



I. Mesodesma {^Davila) planum Hanley. 



1843. Mesodesma plammi Hanley, Proc. Zool. Soc. London, p. 102. 



1853. Davila polita Gray, Ann. Mag. Nat. Hist., (2) XI, p. 44. 



1854. Mesodesma plana Reeve, Conch. Icon., VIII, Mesodesma, pi. III, fig. 16. 



1856. Mesodesma plamim Hanley, Rec. Biv. Shells, Appendix, p. 341, suppl. pi. XII, fig. 19. 



1857. Davila plana Tryon, Amer. Journ. Conch., IV, p. 126. 



1887. Mesodesma [Davila] planum von Martens, Journ. Linn. Soc. London (Zool.), XXI, p. 215. 



1890. Mesodesma plana ând Davila plana Paetel, Cat. Conch. Samm., III, pp. 65, 66. 



1895. Davila polita Dali, Proc. Malacol. Soc. London, I, p. 213. 



1903. Mesodesma plana Hidalgo, Obras Malacol., II, p. 65. 



1905. Mesodesma plana Hidalgo, Cat. Filip., p. 304. 



1909. Davila plana Hedley, Proc. Linn. Soc. N. S. Wales, XXXIV, p. 435. 



19 10. Davila plana Hedley, Austral. Ass. Adv. Sci., XII, p. 35. 



1914. Mesodesma [Davila) planum Lamy, Journ. ConchylioL, LXII, p. 58. 



1928. Mesodesma plana Faustino, Summary Philippine Mar. Freshw. MolL, p. 112. 



Mesodesma [^Davila) planum has a fairly thick, trigonal ovate, and very inequilateral 

 shell, ornamented with microscopic, concentric rugae. The shell in the "Siboga" collection, which 

 I assign to this species, is of a yellowish colour. 



Distribution : — M. [D.) planum has been recorded from the Philippines, Australian 

 Waters and Mergui. 



In the "Siboga" collection it is represented by a single shell from the Anchorage off 

 Dongala, Palos Bay, Celebes (St. 86). 



1) Gray, J. E. — Ann. Mag. Nat. Hist., (2) XI, p. 44 (1853), see also Dall op. cit., p. 913 (1895). 



2) Dall, W. H. — Proc. Malacol. Soc. London, I, p. 213 (1895) and loc. cit., p. 911 (1895). 



