53 



i88g. Arca [Barbatia) mollis Kobelt, in Martini Chemn. Conch.-Cab., (N. F.), VIII (2), Arca, 



p. 128, pi. XXXIII, figs. 5, 6. 

 1890. Arca [Barbatia) tenella Kobelt, op. cit., p. 155, pi. XXXIX, figs. 5, 6. 

 1890. Arca [Acar) teyiella Paetel, Cat. Conch. Samm., III, p. 214. 

 1896. Barbatia tenella Casto de Elera, Cat. Sist. Filip., p. 803. 

 1899. Arca tenella Hedley, Mem. Austral. Mus., III, pp. 492, 528. 

 1899. Barbatia tenella Melvill & Standen, Journ. Linn. Soc. London (Zool.), XXVII, p. 185. 



1903. Arca [Barbatia) tenella Smith, Faun. Geogr. Maldive Laccadive Archipel. II, p. 624. 



1904. Barbatia tenella Lamy, Bull. Mus. d'Hist. Nat. Paris, X, p. 274. 



1905. Arca tenella Hidalgo, Cat. Filip., p. 374. 



1907. Arca [Acar) tenella Lamy, Journ. Conchyliol., LV, p. 93. 



1909. Arca [Acar) tenella Lamy, Mém. Soc. Zool. France, XXII, p. 336. 



1909. Arca [Acar) tenella Melvill, Trans. Linn. Soc. London (Zool.) XIII, p. 122. 



1909. Arca [Acar) tenella Lynge, D. Kgl. Dansk. Vidensk. Selsk. Skr. Nat.- Math., (7) V, p. 117, 



pi. I, figs. II — 13. 



1910. Arca tenella Hedley, Austral. Ass. Adv. Sci., XII, p. 344. 



1911. Arca [Acar) tenella Pelseneer, "Siboga" Lamellibranches (Anat.), p. 13, pi. III, fig. 9. 

 19 17. Arca [Acar) tenella Lamy, Bull. Mus. d'Hist. Nat. Paris, XXIII, p. 33. 



1929. Arca [Acar) tenella Dautzenberg, Faun. Colon. Français., III. Fasc. IV, p. 577. 



I agrée with Lamy that this species should be referred to the subgenus Acar and not 

 Barbatia. Lamy in his account bas given the diagnostic characters of the species, and also 

 included notes on its distribution. 



Distribution : A. tenella has a wide distribution in the Red Sea and the Indo-Pacific. 



The "Siboga" Expédition obtained a fair number of shells from the Anchorage off 

 Labuan Pandan, Lombok (St. 34), St. 90 (1° 17^.5 N., ii8°53'E. 281 mètres), Muaras Reef, 

 east coast of Bornéo (St. 91), St. 98, St. 103, 225^ and Zuid Island (Saleyer). 



Subgenus Fossularca Cossmann. 



1887. Fossularca Cossmann, Ann. Soc. Malacol. Belgique, XXII, p. 138. 



1907. Fossularca Lamy, Journ. Conchyliol., LV, p. 4. 



1925, Fossularca Woodrin^, Miocène MoUusks from Bowden, Jamaica, Pelecypods etc., p. 50. 



Dall ^) treats Fossularca Cossmann as a section of Barbatia Gray, but I agrée with 

 Lamy that it is possible to distinguish it as distinct. For the définition of the subgenus I hâve 

 followed Lamy. A. {F.) guadrilatera Lamarck was designated as the génotype by Cossmann. 



I. Arca [Fosszilarca) sculptilis Reeve. 



1844. Arca sculptilis and A. Zebuensis Reeve, Conch. Icon., II, Arca, pi. XVII, figs. 118, 117 

 (not 120) ^). 



1844. Arca sculptilis and A. Zebuensis Reeve, Proc. Zool. Soc. London, p. 128. 



1845. Arca sculptilis and A. Zebuensis Catlow & Reeve, Conch. NomencL, p. 51. 



1848. Arca sculptilis and A. zebuensis Nyst, Mém. Acad. Roy. Belgique, XXII. pp. 66, 78. 

 1860. Arca sculptilis and A. Zebuensis Reeve, Elem. Conch,, II, p. 93. 

 1885. Arca [Barbatia) sculptilis Smith, "Challenger" Lamellibranchia, p. 262. 

 1889. Arca (s. s.) Zebuensis Kobelt in Martini, Chemn. Conch.-Cab., (N. F.), VIII (2), Arca, 

 p. 86, pi. XXIII, figs. 7, 8. 



i) Dall, W. H. — Trans. Wagner Free Inst. Sci. Philadelphia, III, p. 615 (iJ 



2) As Smith pointed out (Rept. Voy. "Alert", p. m, 1886) the figure numbers of the species A. symmetrica and A. zebuensis 

 on pi. XVII of Reeve's Monograph in the Conch. Iconica hâve been reversed. I hâve examined the types of the two species in the 

 collection of the British Muséum (Nat. Hist.), London, and am able to confoim Smith's conclusions. 



