" * 
the Family Osteodesmacea. 163 
OsrEoprsua, Deshayes, and supposing it identical with 
Lamarck's Anatina myális, has already been referred 
to. The present purpose is to point out another serious 
error of that naturalist, in his generic description, which 
it is the more important to correct, since, like the first 
mentioned, it has been adopted by M. Rang, ‘in his 
Manuel des Mollusques, p. 325. 
It consists in stating the shell to be * iniquiselgs, la ai 
valve gauche, plus bombée que la droite," when the re- 
verse is the case, and it should read “la valve droite 
plus bombée que la gauche." It might be supposed 
: that. this was a misprint only, did we not find the same 
mistake repeated on plate 76, f. 8, a, to which figure he 
refers at the bottom of the plate as “ montrant la piece 
calcaire du tégument sur la valve droite,” . when in fact 
it is the left valve which i is represented. It is. difficult 
to conceive by what strange inadvertence, an observer 
so accurate as M. de Blainville, could have repeated an 
error of this nature ; when a glance at the impressions, 
even as represented fig. 8, of the same plate, would have 
made it apparent at once ; unless indeed he was misled 
by the peculiar position of the ligament, which is not 
spoken of either by himself, or any of the others who 
have characterized the genus. It is not the less certain, 
: however, that this peculiarity does exist, as is sufficiently 
apparent in the specimen before me, from which the 
preceding description was drawn up. M. Deshayes 
speaks of the ossiculum as triangular, but in the very 
fresh and perfect shell under observation, (for the op-. 
portunity of examining which, I am indebted to the 
kindness of the President of this Society, to whose col- 
lection it belongs,) it is. very nearly a complete semi- 
