the Family Osteodesmacea. E 
T. corbuloides, Deshayes, under which belief Dr. 
Storer, in his excellent translation of that work, speaks . 
of this latter species in a note, page 4, article Turacta, 
as existing along the whole coast of New England. 
he close resemblance, in the outline of our shell, to 
the figure of Kiener, rendered this conclusion almost 
unavoidable, without an opportunity of comparing the 
shells themselves. Through the kindness of Dr. J. C. 
Jay, of New York, I am in possession of a fine speci- 
men of 'T. corbuloides, from the Mediterranean, which 
differs from T. Conrádi in the following essential 
particulars: it is more elongated jn proportion to its 
height, much more inequilateral, more broadly and 
unevenly truncated, and externally covered with fine 
granulations, making it rough to the touch, (not un- 
like fine sand-paper;) which is not the case with ours - 
at all, except near the beaks, and shere: "kanile per- 
“ceptible. 
But the difon most to be relied upon, and in fact. 
sufficient in itself to -warrant a distinction, because it 
manifests a different conformation in the animals, is that 
of the muscular and palleal impressions. The posterior 
muscular impression, both in the shell before me and as 
represented in pl. 76,:f. 7, Man. de Malac., is small and 
irregularly rounded, and the palleal impression, as 
shown. by the plate, is excavated posteriorly in an irreg- 
ular, and in the specimen in a regular semicircular form ; 
whereas, in T. Conrádi, the first is subtriangular or 
pyriform, and the latter forms posteriorly a deep and 
almost acute angle. 
T. convéxa differs from our species in the shape of its 
ligamentary supports, is covered with a rough, ferruginous 
