168 PALEONTOLOGY OP 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 Dentaliidie." 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. Jiamatum." 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 shews it to be the same by his 

 references to the same page, plate, and figure where his D. falcatum is 

 given. It may be that in the shells themselves the curvature, coupled with 

 some at present unknown feature, would distinguish them as generically 

 separable from the true Dentaliu, but I see no reason, as far as the casts show, 

 for considering them difi"erent from shells of that genus, except the greater 

 and iiTegular curvature. 



