82 PALEONTOLOGY OF NEW YORK. 



Genus CAMAROSPIRA, gen. nov. 



PLATE XLir. 

 1867. Camarophoiia, Hall. Palseontology of New York, vol. iv, p. 368, p), Ivii, figs. 40-45. 



Shells essentially meristelloid in external and internal characters. The 

 important difference from allied genera lies in the fact that the dental plates of 

 the pedicle-valve, instead of resting upon the bottom of the valve, are more 

 strongly convergent than in Merista, Meristella, etc., uniting before they 

 reach the internal surface of the valve, thus restricting the impression of the 

 pedicle-muscle to a distinct chamber or .spondylium, which is supported 

 by a low median septum. In the typical species (C. eucharis, Hall) this 

 chamber has the same extent as the deep pedicle-cavity in Meristella, 

 that is, about one-fourth the length of the valve, while the septum ex- 

 tends for a short distance beyond its anterior margin, dividing the scars 

 of the adductor and diductor impressions. In this respect the internal 

 structure of this valve is similar to that of the corresponding valve of 

 Pentamerus. 



In the brachial valve the hinge-plate is supported by a median septum 

 slightly longer than that of the opposite valve, and the narrow, cordate mus- 

 cular impression, which it divides medially, is considerably thickened. The 

 valve bears everted spirals similar to those of other members of this group, 

 but the specimens studied were not in a condition of preservation adapted to 

 the determination of the structure of the loop. 



The only species known to possess the peculiarities described is the Camaro- 

 phoria eucharis, Hall, from the Corniferous limestone of Indiana and the Province 

 of Ontario. 



