BRA C HI O POD A — TEL O TREMA TA . 



359 



425. M. nasuta (Conrad). (Figs. 472 and 473.) Devonic. 



Subrhomboidal with greatest width near the middle. Pedicle 

 valve gibbous with prominent beak. Anterior margin marked by 

 a nasute extension. Brachial valve moderately convex and ab- 

 ruptly elevated toward the front into a short, rounded fold. Beak 

 moderately incurved. 



Fig. 473. Meristella nasuta, Onondaga form (Pal. N. Y., IV.). 



Schoharie and Onondaga of New York, Ohio, Kentucky, Indiana, 

 Nevada, Ontario. 



426. M. barrisi Hall. (Fig. 474.) Devonic. 



Ovoid, more or less elongate/sinuate anteriorly. Pedicle valve 

 depressed toward the front, with beak arching and not closely in- 

 curved. Brachial valve abruptly elevated near the anterior mar- 

 gin. Surface smooth or concentrically striated. 



Marcellus and Hamilton of New York. Also in Russian Urals. 



Fig. 474. Meristella barrisi (Pal. N. Y., IV.). 



CXXV. Pentagonia Cozzens. 



Pedicle valve with a very broad median sinus outside of which 

 the lateral slopes are very abrupt. Muscular impressions like 



