248 TESTACEOUS MOLLUSCA. 



M. Perna. Lam. 20.— Mya- P. Lin 1113 1—Knorr 4. t. 15. f. 

 4. — Born t. 7.f 7 ? — Narrow and elongated, ventricose, straight, 

 under its epidermis, livid purple becomiug rich purple when 

 polished, (the shell is generally obtained in that state from being 

 almost always worn and eroded) except at the flattened posterior side 

 which is white and almost running in a straight line to the base ; 

 hinge margin very long; within dark purple anteriorly, pearly white 

 posteriorly ; hinge with two strong teeth in one valve ; a single 

 acute one in the other. 1^. . 4. Oran. The epidermis of aged spe- 

 cimens is brownish black, of adult, rufous or chesnut near the ventral 

 edge, and greenish fulvous with arrow-headed chesnut or dark mark- 

 ings toward the beaks — It is not improbable that this may prove the 

 same species as the next. 2 



M. Afer. Gmel. 3358.— Lam. 21. — M. Ungulatus. Var. D. 

 p. 310.— Bl. t. 64./. 2.—Ch.f 739. to U.—Kn. 4. t. 15. f. 5 — 

 E. t. 218./. 1. Oblong, triangular, dilated at the margin, with zic 

 zag lines under a greenish fulvous epidermis, tumid posteriorly near 

 the beaks : hinge with two teeth in one valve and one in the other. 

 Barbary fyc. 4J-. 



M. Achatinus. Lam. 22. Oblong-triangular, with a reddish- 

 fulvous cuticle, compressed and somewhat angulated anteriorly and 

 rather tumid posteriorly : internal nacre of a brilliant livid violet 

 colour. 4. Brazil. 3 



2 M. Deshayes considers that this is the same species with the 

 M. Elongatus of Chemnitz. (/. 738.— TV. t. 12, f. 25.— E. t. 219. 

 /. 2. — Mytilus Perna. D .p. 312. — Mya P. Schroet. Ein. t. 2. 

 /. 7.) Lamarck's specimen of his Elongatus. (Lam 12.) is cer- 

 tainly the same as those from which I have drawn my description, 

 many individuals of which agree perfectly with his description of 

 M. Perna — But the locality of Chemnitz's species (Magellan) and 

 the evident projection of the posterior side, renders it possible that 

 his shell at least is a different species. 



3 Lamarck with some doubt refers to the M. Latus. of Chem- 

 nitz for a figure of this species. Should the synonym prove correct 

 (which I confess I doubt, as I have seen a Brazilian specimen well 

 agreeing with the description of Achatinus, and to all appearance 

 distinct from the New Zealand species) the prior name of Canali- 

 culus.(Martyn. U. C. t. 78.— W. t. 12. f. 47,— M. Latus. Ch.f. 

 747- — Z), in part. p. 311.) must be restored. Of this latter shell there 

 are two varieties. The one elongated and covered with a blackish 

 cuticle, which becomes of a bright verditer green at its edge ; and 

 internally white, with a purplish tint on its submarginal muscular 

 impression : the other, more solid much broader and rounded, the 

 cuticle dark olive and the internal nacre near the muscular* car, of 

 a purplish brown. 



