BRACHIOPODA — TELOTREMATA. 



301 



middle and abruptly rounded toward the cardinal extremities, nar- 

 rowing toward the front. Surface marked by simple radiating 

 striae. Distinguished from R. ceqniradiata by its different form, 

 larger size and more prominent striae. 



Oriskany of New York, Pennsylvania, Maryland, Virginia, 

 Quebec. 



292. R. cayuga Hall and Clarke. (Fig. 374.) Devonic. 



Lenticular, often large, suboval in marginal outline. Valves 

 subequally biconvex. Very similar to R. ceqniradiata, from which 

 it differs principally in its suboval marginal outline and in its large 

 size. 



Upper Oriskany (Decewville) of Ontario. 



FlG. 374- Rensselczria cayuga. 

 (After Hall and Clarke.) 



Fig. 375. 



Cryptonella planirostris with 



beak of pedicle valve enlarged ; d-e, C. recti- 

 rostris (Pal. N. Y. , IV.). 



LXXXIX. Cryptonella Hall. 



Elongate-oval, unequally convex, usually without median fold 

 or sinus. Pedicle valve with extended and incurved beak, per 

 forated by a terminal foramen. Surface smooth or marked by 

 concentric striae. Shell structure finely punctate. Devonic-Mis- 

 sissippic. 



293. C. planirostris Hall. (Fig. 375, a-c.) Devonic. 



Often subpentagonal in outline. Pedicle valve with moderately 

 incurved beak. Brachial valve much shorter than the pedicle 

 Surface marked by fine concentric striae. 



Marcellus and Hamilton of New York. 



