1891.] MR. E. A. SMITH ON SHELLS FROM ADEN. 431 



243. Arca imbricata, Bruguiere. 



Hab. West Indies, Fernando Noronha, S. Africa, Indian Ocean, 

 N.E. and N. Australia. 



With this species I unite A. umbonata, Lamk., A. cunealis. Reeve, 

 A. kraussi, Philippi, and A. americana, d'Orbigny. 



244. Arca (Barbatia) obliquata, Wood. 

 Hab. South Africa, 



Reeve's A. obliquata has been shown by Philippi and Lischke 

 to be distinct from Wood's species, and it has been renamed 

 A. decurvata by the latter author. I am of opinion that it is the 

 same as A. sinensis of Philippi, 



245. Arca (Barbatia) lima. Reeve. 

 Hab. Philippine Islands, Cape York. 



A. trapezina, Lamarck, as determined by Reeve, is probably a 

 form of this species, which is extremely variable in outline, no two 

 specimens being quite alike. 



246. Arca (Acar) domingensis, Lamarck. 



This species, as shown by Lischke, has a world-wide distribution. 

 In addition to the synonymy quoted by that author (Jap. Meer. 

 Conch, ii. p. 142), I may mention that A. dubia of Baird also 

 belongs to this species, 



247. Arca (Anadara) scapha, Chemnitz. 

 Hab. Philippines, Indian Ocean, Natal, Suez. 



248. Arca (Anadara) antiquata, Linn. 



Hab. Australia, Indian Ocean, Mozambique. 



This species was described by Reeve under the name of A. maculosa, 

 under the impression that the "spots" on the posterior side con- 

 stituted a good specific character. On carefully examining his type 

 I find that the so-called "spots" are merely pieces of epidermis 

 left upon the ribs, all of which might be removed with the point of 

 a knife. The name maculosa therefore being unsuitable, had better 

 be cast aside ; and as Hanley (Ipsa Linn. Conch, p, 93) declares 

 that the A. antiquata of Linn, is the same as Reeve's species, we 

 can apply that designation instead. It seems to me very probable 

 that an extended series of specimens would show that this species 

 and A. scapha should be united. 



249. Arca (Anadara) erythr^ensis, Jonas. 

 Hab. Eed Sea ; Zanzibar (Mus. Cuming). 



250. Arca (Anadara) holoserica, Reeve. 



Hab. Philippines, Madagascar, Mauritius, East Africa. 



According to Morch, whose opinion has been followed by von 

 Martens and Kobelt, this species is synonymous with A. uropygome- 

 lana of Bory de St. Vincent. All we know about that species is its 



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