BRACHIOPODA—PROTREMATA, 



235 



Concavo- to plano-convex. Pedicle valve depressed convex. 

 Cardinal spines slightly oblique, about 14. Surface of both valves 

 with rather coarse radiating ribs, 3 or 4 in a space of 2 mm. at the 

 anterior margin; the lateral ribs often curve slightly anteriorly as 

 they approach the margin. Very fine concentric lines also present. 

 Large shell measures 14 mm. in length by 22 mm. in width. 



Decker Ferry of New Jersey, Cobleskill, etc., of New York. 



119. C. hemisphericus Hall. (Fig. 285, a-b.) Devonic. 



Hinge line often much extended and with 3, 4 or more spines on 



Fig. 285. a, b, Chonetes hemisphericus ; c, d, C. pusillus ; e,f, C. aurora, with 

 enlargement of surface ; g, h, C. logani, with enlargement of surface ; i, C. mesolobus. 

 (After Hall.) 



each side of the middle. Pedicle valve very ventricose with promi- 

 nent, incurved umbo. 



Onondaga of New York, Nevada, Ontario. 



Shell about ^ inch or 1 inch wide. 



120. C. mucronatus Hall. (Fig. 286.) Devonic. 



Small (about y^ inch in width), moderately convex with rather 



distant and strong radial striae. Cardinal spines, 2-3 on each 



Fig. 286. Chonetes mucronatus, X 2 - (After Hall.) 



side of the beak, curving out so abruptly as to become parallel to 

 the hinge line. 



Oriskany-Hamilton of New York, Nevada, Ontario, Quebec. 



