PAL2E0NT0L0GY OF NEW-YORK. 
that I feel compelled to adopt the prior name, which will include those 
described in this volume under the Genus Pal^earca, as well as those 
described by Mr. Billings under the Genera Cyrtodon and Vanuxemia. 
The following is the description given by Mr. Conrad. 
Genus Cypricardites. Equivalved, profoundly inequilateral : hinge with 
“ four or five unequal cardinal teeth, anterior one largest and most 
prominent; lateral teeth short, and very remote from the cardinal 
teeth.” 
“ This genus is allied to Pterinea of Goldfuss, but is never properly alated, nor 
lias it the very large muscular impressions of that genus : the cardinal and lateral 
^ teeth are also different; the anterior cicatrix is often deeply impressed ; the po- 
(C sterior one not visible in casts of the interior. The genus abounds in the Silurian 
“ rocks, but I have not seen a species from any more 
“ recent formation*.” 
Mr. Conrad describes sixteen species under this 
genus, among which were included the C. bisulca- 
ta since described by de Verneuil as the type of 
the Genus Grammysia, under the name G. hamil- 
Cypricardites (Conrad)!. tOTlCUsis. 
* When these remarks were written, the Hamilton and Chemung groups were regarded by the New-York 
geologists as Silurian, and as being the equivalent of the Ludlow rocks of England. 
t This figure is copied from the original figure of Mr. Conrad, accompanying his description of the genus 
in 1841. The plate upon which this occurs was engraved to accompany the Annual Report of 1841; but, 
unfortunately, only a small number were ever distributed, so far as known to the writer. The same plate 
contains illustrations of the Genera Nuculites, Lyrodesma, Orthonota, Cyrtolites, Orthostoma, Dictyo- 
crinus, Jlspidolites and Dicranurus, as well as one species of Platyceras; all genera proposed by Mr. 
Conrad. 
