the Family Osteodesmacea. 171 
Ossrnvarrows. The figures and descriptions given by 
British authors of Cama praténuis, Petiver, Mya præ- 
ténuis, Pennant, Donovan, Wood, Dillwyn, Turton, 
(Conch. Dict.) Lieva preténuis, Montagu, [ Suppl.], 
Anatina preténuis, Turton (Bivalves) and Brown, seem 
to answer so closely to Mr. Conrad’s shell, that it appears 
doubtful to me whether they are not identical. This 
cannot however be determined with certainty, without 
a comparison of the shells themselves, which it is not 
possible to ‘make at present. If the preíénuis: prove . 
specifically distinct from the Léana, there is no doubt of 
it being generically the same; and it should therefore 
be received as €. preténuis, mi. 
In this- instance, as in many others, we can only re- 
gret that we are so deficient in the British nin d | 
especially ¢ marine ones. Should these re 23 
the eye of naturalist in England, who ET 
the trouble a oria to the Boston Society of Natu- 
ral History such as he might have it in his power to 
collect, he might rely on promptly receiving: our own 
species in exchange, and would be instrumental in re- 
moving.a grievous stumbling block from the path of 
dá those in this country, who take an interest in the ad- 
. vancement of this department of Natural History. 
‘ kl d ParELLOIDEA AMENA. 
Synonyms. Patélla amena, Say, Journ. — Nat. 
iSc; IT, 993. 
Patelloidea amena, C'ovrHovy. 
Animal, oblong oval, moderatély convex, aoe 
with a thick, muscular, smooth, dilatable, elongated-oval 
