i pre of the foot. - 
168 Couthouy's Monograph on 
very distinct, however, the European shell being nearly 
or full twice as large as ours, more elongated, more 
broadly truncated, more inequilateral, the basal margin 
. less. regularly curved, thicker, and covered with a much 
stronger and more opaque epidermis. 
Since the foregoing remarks were written, Dr. Gould 
has informed me, that several years since, he observed 
the peculiarity of the ossiculum in O; hyalina, and re- 
ferred it in consequence to genus Lyonsia, Turton. Tt 
is noted in the Catalogue of Animals and Plants of Mass. 
p. 25, as Aurnipzsua corbuloides, Lam.. 
a 
M. Deshayes having formed his Family Osteodesma-: - 
cea, to embrace such shells as are furnished with - am 
ossiculum of « some form or other, supported at t the hin 
and havin à 
assigned them ii in his classification. ; j | 
I allude to those shells which are furnished with à 
internally: projecting, spoon-shaped process for the m 
As the method of Pi. vit. ne 
