BRACHIOPODA — TELOTREMATA, 



329 



351. S. iowaensis Owen. (Figs. 418, 419.) Middle Devonic. 



Often inequilateral. Hinge line much extended. Valves often 



nearly equally convex. Beak of pedicle valve much elevated and 



slightly incurved. Whole surface, including fold and sinus and 



KlG 41 S. Spirijer iowatnsis. (After Nettleroth ) 



Fig. 419. Spirifer iowaensis (S. pennatus Owen) X Yi w ith enlargement of surface. 

 (After Hall.) 



numerous plications, covered with slender, radiating striae crossed 

 by concentric growth lines. 



Hamilton of Kentucky, Michigan, Indiana, Illinois, Wisconsin, 

 Iowa, Arctic North America lat. 82 42'. 



352. S. audaculus (Conrad). (Fig 420, a.) Devonic. 



Ventricose when old. Pedicle valve with high, concave cardinal 

 area and incurved beak. Cardinal area of brachial valve linear. 

 Mesial fold and sinus well marked. Surface covered with many 

 concentric lines and plications marked with radiating striae. Differs 

 from S. granulosus in being smaller and in that the cardinal area of 

 the brachial valve is linear. 



Marcellus and Hamilton of New York, Kentucky, Indiana, Wis- 

 consin. 



