248 TESTACEOUS MOLLUSGA. 
M.. Perna. Lam. 20.—Mya- P. Lin 1113?—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. 14..4. Oran. The epidermis of aged spe- 
cimens is brawnish black, of adult, rufous or chesnut near the ventral 
edge, and greenish fulvous mith arrow-headed chesnut or dark mark- 
mgs toward the beaks—It is not improbable that this may prove the 
same species as the next. ” 
M. Arer. Gmel. 3358.—Lam. 21.—M. Uneutatus. Var. D. 
p. 310.—Bl. t. 64. f. 2.—Ch. f. 739. to 41.—Kn. 4. t. 15. f. 5.— 
E. t. 218. f.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 §c. 43. 
M. Acuatinus. 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 
* M. Deshayes considers that this is the same species with the 
M. Elongatus of Chemnitz. (f. 738.—W. t. 12, f. 25.—E. t. 219. 
f. 2.—Mytitus Perna. D .p. 312.—Mya P. Schroet. Ein. t. 2. 
f. 7.) Lamarck’s specimen of his Etoncatus. (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. Rerna—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. Larus. 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 Cana i- 
cuLus.(Martyn. U. C.t. 78.—W. t. 12. f. 47,—M. Larus. Ch. f. 
747.—D, 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 musculars car, of 
a purplish brown. 
