REPORT ON THE LAMELLIBRANCHIATA. 57 



Subfamily Mactrin.e. 

 Mactra, Linue. 



Mactra {Mactrinula) pUcataria, LiiiiR'. 



Mactra iMcataria, Linne, Syst. Nat., ed. 12, p. 1125. 



Mactra pUcataria, Chemnitz, Conch. -Cab., vol. vi. p. 213, pi. x.x. figs. 202-204. 



Mactra plicataria, Reeve, Con. Icon., vol. viii. fig. 26. 



Mactra {Mactrinula) jilicataria, Kobelt, Illust. Conch., p. 324, pi. xciii. fig. 8. 



Mactrinula pUcataria, H. and A. Adams, Genera, vol. iii. pi. xcix. figs. 2, 2a. 



Mactrinula plicataria, Chenu, Manuel Conch., vol. ii. p. 55, fig. 226. 



Habitat. — Cape York, North Australia, in 3 to 12 fathoms (Challenger); Java 

 (Linn.); Sumatra (Reeve); Tranquebar (Chemnitz). 



Only a single small specimen about half an inch in length was obtained. This is 

 not quite typical, having the concentric riblets more or less obsolete, except down the 

 anterior side, in this respect more like Mactra Uvvis, Chemnitz, which I believe is 

 another form of this species. 



Mactra [Mactrinula) de2)ressa, Reeve. 



Mactra depressa (ISpengler) (teste Reeve), Skrivt. af Naturhist. Selskabet, 1799, vol. v. p. 118. 

 Mactra depi-essa, Reeve, Conch. Icon., vol. viii. fig. 67. 

 Mactra ovalina, Reeve (? Lamarck), Conch. Icon., fig. 66. 



Habitat. — Port Jackson, in 2 to 10 fathoms (Challenger and G. F. Angas); also 

 Port Philip (Angas and Brit. ]\Ius.). 



I see no sufhcieut reason for separating the above two forms. Probably Reeve was 

 influenced by the localities attached to the specimens in Cuming's collection. " West 

 Columbia " I merely regard as one of the numerous geographical errors which occur 

 throughout that collection, many of which unfortunately have found their way into print in 

 the works of Reeve and Sowerby. Mactra angulifera, Deshayes, is scarcely sufficiently 

 distinct to warrant its specific separation. The figure in Delessert's Recueil, pi. iii. 

 figs. 7a, b, is a verj' cUfierently shaped shell to that represented in the Conchologia 

 Iconica. 



I have little doubt that Reeve's identification of this species with the Mactra 

 depressa of Spengler is incorrect. It is described by the latter author as having a 

 sulcated lunule and a liueated area (" vulva arcuata, sulcata, ano lineato "). It is also 

 characterised as equilateral, the posterior carinse are not mentioned, and it is said 

 to come from the coast of Guinea. The name " depressa " has been subsequently 

 employed by Deshayes for a fossil species (Coq. foss. de Paris, vol. i. p. 32). 



(ZOOL. CHALL. EXP. — PART XXXV. — 1885.) ^I HI 8 



