BRACHIOPODA—PROTREMATA. 



229 



Cobleskill of New York, Greenfield of Ohio, etc. 



107. S. woolworthana (Hall). (Fig. 278.) Devonic. 



Semielliptical. Both valves depressed convex at beak, concave 



toward the front. Beaks small. Surface with small, round, crowded, 



FlG. 278. Schuchertella woohvorthana. (After Hall.) 



radiating striae, increasing by interstitial addition, crossed by fine 

 growth striae and few larger lines of growth. Interior of pedicle 

 valve marked by a large, flabellate muscular area. 

 Helderbergian of New York. 



108. S. pandora (Billings). (Fig. 279.) Devonic. 



Differs from S.cJiemungensis in the more regularly bilateral posi- 

 tion of the umbo and in its lesser prominence ; also in the less 

 rectangular form of the shell. 



Schoharie and Onondaga of New York, Ohio, Ontario, Nevada. 



FlG. 279. Schuchertella pandora. 



109. S. arctostriata Hall. (Fig. 280, a-b.) Devonic. 



Semielliptical or semicircular, often unsymmetrical. Pedicle 

 valve slightly convex at umbo, flattened anteriorly ; beak often dis- 

 torted ; cardinal area usually unequal on the two sides of the fora- 

 men. Brachial valve usually depressed convex. Surface covered 

 with sharp, close, crenulated, radiating striae, increasing mainly by 



