34 



i86o. Arca zébra Reeve (non Sowerby), Elem. Conch., II, p. 93. 



1869. Arca iiDibonata Dunker (non Lamarck), Cat. Mus. Godeffroy, IV, p. 114. 



1874. Arca ventricosa Dunker, Cat. Mus. Godeffroy, V, p. 174. 



1889. Arca (s. s.) ventricosa and A. (s. s.) truncata Kobelt in Martini Chemn. Conch. -Cab. (N. F.), 



VIII (2), Arca, p. 61, pi. XVIII, figs. i, 2 and p. 133, pi. XXXIV, figs. 7, 8. 



1890. Arca truncata, A. ventricosa and A. zébra Paetel, Cat. Conch. Samm., III, p. 212. 

 1898. Arca zébra Melvill & Sykes, Proc. Malacol. Soc. London, V, p. 45. 



1904. Arca ventricosa Lamy, Bull. Mus. d'Hist. Nat. Paris, X, p. 271. 



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



1906. Arca ventricosa Lamy, Bull. Mus. d'Hist. Nat. Paris, XII, p. 316. 



1907. Arca ventricosa Lamy, Journ. Conchyliol., LV, p. 39. 



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



1917. Arca ventricosa Lamy, Bull. Mus. d'Hist. Nat. Paris, XXIII, p. 27. 



1927. Navicula ventricosa Cox, Rept. Palaeont. Zanzibar, p. 93. 



1927. Arca ventricosa Tomlin, Trans. Zool. Soc. London, XXVI, p. 303. 



This species, which is widely distributed in the Indo-Pacific, is represented in the "Siboga" 

 collection by two adult shells (47 mm. long) taken at St. 225 (5700 m. N., 279° E. from South 

 point of South Lucipara Island and Ambon Anchorage (St. 231) respectively and the left valve 

 of a young shell collected at Macassar. 



3. Arca {Navicula) navictilaris Bruguière, var. linter Jonas. 



1845. Arca linter Jonas, Zeitschr. Malakozool., p. 172. 



1847. Arca linter Philippi, Abbild. Beschreib. Conch., II, p. 209, Arca, pi. III, fig. l. 



1848. Arca linter Nyst, Mém. Acad. Roy. Belgique, XXII, p. 42. 



1882. Arca 7iavicularis var., Dunker, Ind. Moll. Mar. Japon., p. 232, pi. XIV, figs. 16, 17. 

 1888. Arca navicnlaris var., and A. Imter Kobelt in Martini, Chemn. Conch. -Cab. (N. F.), 



VIII (2), Arca, pi. XVII, figs. 3, 4; p. 19, pi. VI, figs. i, 2. 

 1890. Arca linter Paetel, Cat. Conch. Samm., III, p. 211. 



1907. Arca [Arca) navicnlaris var. linter Lamy, Journ. Conchyliol., LV, p. 20. 

 1909. Arca navicnlaris var. linter Lynge, D. Kgl. Dansk. Vidensk. Selsk. Skr. Nat.-Math., (7) 



V, p. 109. 



In treating this form as a distinct variety I hâve followed Lamy, as I hâve not sufficient 

 material to décide whether it is not only a slight variation of the typical A. navictdaris as 

 Smith ^) considered it to be. Ail the spécimens collected by the "Siboga" Expédition are young 

 shells and in this stage at least they appear to represent quite a distinct variety. No spécimens 

 of the typical A. navicnlaris were obtained by the "Siboga" Expédition. 



Distribution : — This variety appears to hâve a wide distribution in the Red Sea and 

 the Indo-Pacific Area. It is known from Suez to Madagascar and from Aden through the Gulf 

 of Manaar, Gulf of Siam to Torres Strait and even south-east Australia : northwards in the 

 Pacific, it is also recorded from the Chinese and Japanese waters. 



The "Siboga" Expédition collected spécimens of this variety on the bank between the 

 islands of Bahuluwang and Tambolungan, South of Saleyer (St. 66), West of Kwandang Bay 

 entrance (St. 116), Anchorage east of Dangar Besar, Saleh Bay (St. 313) and at Macassar. 



l) Smith, E. A. — "Challenger" Lamellibranchia. p. 259 (1S84). 



