51 



1891. Barbatia {Acar) donaciforrnis and B. [A) plicata Kobelt, op. cit. p. 188, pi. XL VI, fig. 5 



and p. 19s, pi. XLVII, fig. 5. 

 1891. Barbatia [Acar] domingensis Sntîith, Proc. Zool. Soc. London, p. 431. 



1894. Arca {Acar) plicata Henn, Proc. Linn. Soc. N. S. Wales, (2) IX, p. 180. 



1895. Arca [Barbatia) domingensis Pilsbry, (non Lamarck), Cat. Mar. Moll. Japan, p. 149. 

 1897. Arca plicata Watson, Journ. Linn. Soc. London (Zool.), XXVI, p. 273. 



1897. Arca divaricata Sowerby, Mar. Shells S. Africa, Suppl., p. 27. 



1898. Barbatia [Acar) pusilla Melvill & Standen, Journ. Conch., IX, p. 81. 



1899. Barbatia [Acar) divaricata and B. [A.) domingensis Melvill & Standen, Journ. Linn. Soc. 



London (Zool.), XXVII, p. 186. 



1900. Arca [Acar) domingensis Dautzenberg, Mém. Soc. Zool. France, XIII, p. 236. 



1900. Arca squamosa B. Newton, Geol. Mag., VII, p. 546. 



1901. Barbatia divaricata Sturany, Denkschr. Kais. Akad. Wiss. Wien, Math.-Nat., LXIX, p. 289. 



1902. Barbatia Domingensis Shopland, Proc. Malacol. Soc. London, V, p. 178. 



1904. Barbatia squamosa Pritchard & Gatliff, Proc. Roy. Soc. Victoria, XVII, p. 241. 



1904. Arca squamosa Lamy, Journ. ConchylioL, LII, p. 142. 



1904. Arca domingensis Smith (non Lamarck), Ann. Mag. Nat. Hist., (7) XIV, p. 12. 



1904. Arca [Acar) plicata Lamy, Bull. Mus. d'Hist. Nat. Paris, X, pp. 274, 275, fig. i. 



1905. Arca divaricata Hidalgo, Cat. Filip., p. 372. 



1905. Arca iridina Lamy, Journ. ConchylioL, LUI, p. 306. 



1906. Arca [Acar) plicata Lamy, Bull. Mus. d'Hist. Nat. Paris, XII, p. 317. 

 1906. Arca [Acar) domingensis Smith, Ann. Mag. Nat. Hist., (7) XVIII, p. 253. 

 1906. Arca domingensis Ovvston, Japan. Loochooan Shells, p. 33. 



1906. Barbatia domingensis Melvill & Standen, Proc. Zool. Soc. London, p. 796. 



1906. Barbatia [Acar) gradata (nec Broderip & Sowerby), Melvill & Standen, op. cit., p. 797. 



1907. Arca [Acar) plicata Lamy, Journ. ConchylioL, LV, p. 80. 



1907. Arca [Acar) plicata Lamy, Bull. Mus. d'Hist. Nat. Paris, XIII, p. 153. 



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



1909. Arca [Acar) plicata Lamy, Mém. Soc. Zool. France, XXII, p. 335. 



1909. Arca [Acar) plicata Lynge, D. Kgl. Dansk. Vidensk. Selsk. Skr. Nat. -Math. (7) V, p. 116. 



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



1911. Arca plicata Pelseneer, "Siboga" Lamellibranches (Anat.), pp. 11, 13. 

 19 17. Arca [Acar) plicata Lamy, Bull. Mus. d'Hist. Nat. Paris, XXIII, P- 32. 

 1917. Arca plicata Odhner, Kungl. Sv. Akad. Handl., LU (N" 16), p. 21. 

 1927. Arca divaricata Tomlin, Trans. Zool. Soc. London, XXVI, p. 304. 



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



There has been a great deal of différence of opinion in référence to the spécifie limits 

 and range of variation and distribution of the species v^hich was figured without any name by 

 Lister, but later called A. plicata by Chemnitz. Lischke was the first to confine into a single 

 species the Indo-Pacific with the West Indian and North American forms and in this has been 

 follovi^ed by Smith, Lamy and Lynge. I, however, agrée with Cooke and Tomlin that there 

 are three well distinguished forms ; A. gradata Broderip & Sowerby from the West Coast of 

 North America, A. domingensis Lamarck from the West Indies and A. {A.) plicata Dillwyn 

 from the Indo-Pacific. The Indo-Pacific form is easily distinguished by its short and stout but not 

 very swollen shell, the much fewer number of ribs, the central area with closely placed ribs, the 

 ribs behind the keep running transversely outwards to the edge, the nodules on the ribs rounded 

 and the ventral margin often distorted. 



Distribution: — A. [A.) plicata has a wide distribution in the Indo-Pacific area. It is 

 found as far north as the Gulf of Suez and down south to the Cape of Good Hope ; in the 

 Indian Océan it is found ail round the coasts, while in the Pacific Océan it ranges from Japan 



