and Shells of Massachusetts Bay. 91 
forming almost the entire surface of the shell ; incremen- 
tal strie very minute and numerous; lip sharp and 
smooth, somewhat everted at its inferior junction with 
the columella, which is elevated, strongly arcuated and 
formed by a thjckening and reduplication of the inner 
lip ; near the superior extremity of the columella, a thin, 
vitreous deposit extending over it upon the body of the 
shell, forms a slight umbilicus; aperture oval, effuse, 
occupying nearly the whole inferior portion of the shell. 
Osservations. The aspect of this shell corresponds 
almost precisely with the figures of Sigarétus haliotoi- 
dèus, Lx., given by Montague, Turton and Brown, in 
their works upon British shells. There can, however, be 
no doubt of its being distinct, from the fact that the ani- 
mal, as observed by me, was wholly internal, with a 
muscular, oblong disk or foot like a Patella, and two 
short, thick tentacule; in its contracted state barely 
filling the shell, from which it was easily detached. From 
Velutina it is removed by being furnished with a distinct 
columella, the absence of which is made by Blainville, 
its founder, one of the characteristic marks of that genus. 
From Rafinesque’s description of his genus Oxinoe, it 
appears to me the most appropriate one in which to 
place this shell for the present; hoping that an oppor- 
tunity may hereafter occur to examine it with the animal 
perfect. This latter, which, although the characters 
above specified were distinct enough, was still much in- 
jured by partial decomposition in the stomach of the fish 
whence it was taken. The fish itself was caught off 
Barnstable, in the month of July last. 
