168 PALEONTOLOGY OF NEW JERSEY. 
would probably be rewarded by many new and hitherto unrecognized 
forms. | 
Genus FALCULA Conrad. 
Am, Jour. Conch., vol. 6, p. 77. 
The peculiar shells, or rather internal casts of shells, upon which 
this genus was founded, have all the appearance of shells of the genus 
Dentalium except in the greater curvature, and were originally described as 
such. At the time Mr. Conrad proposed to separate them as a distinct 
genus, he states that ‘“‘under a lens this cast shows a minute, very closely 
granulated surface, slightly iridescent.” He further states that ‘‘this char- 
acter, together with the expanded base, renders it doubtful whether this 
shell belongs to the family Dentalide.” I have in my hands the specimen 
from the collection Acad. Nat. Sci., Phila, which I suppose to be those 
used by Mr. Conrad and which are the only ones known to me; but I can 
not find the peculiar structure of which he speaks. Nor does the expansion 
of the aperture mentioned seem to me to be more than would be pre- 
sented on a cast of a thickened tube by the rounding out, or rapid decrease 
in thickness, of the shell at the aperture. In vol. 5, Am. Jour. Conch., p. 
45, under the original description of the species, Mr. Conrad says: “There 
is one other similar species in India, D. hamatum.” This latter species; 
described by Forbes in the Trans. Geol. Soc., London, vol. 7, p. 138, is 
said by Dr. Stoliczka to prove to be only a cast of a longitudinally ribbed 
species of Serpula, on the examination of the type specimen. Consequently 
it can scarcely be generically identical with this one. Mr. Conrad has also 
created some confusion in regard to the specific name of this shell, as he 
originally described it as Dentalium falcatum, and when making his genus, 
changes the name to Falcula hamatus without the slightest reference to or 
reasons for changing the specific name; but shows it to be the same by his 
references to the same page, plate, and figure where his D. falcatum is 
given. It may be thatin the shells themselves the curvature, coupled with 
some at present unknown feature, would distinguish them as generically 
separable from the true Dentalia, but I see no reason, as far as the casts show, 
for considering them different from shells of that genus, except the greater 
and irregular curvature. 
