BRACHIOPODA—PROTREMATA. 



209 



63. P. hamiltoniae Hall. (Fig. 245.) Devonic. 

 Ovate with broader posterior end. Apex excentric and inclined 



backward. Surface marked by closely arranged lamellose growth 

 lines. 



Hamilton of New York. 



PROTREMATA. 



XXVI. Kutorgina Billings. 

 Inequivalved ; hinge line nearly equal 

 to the greatest width of the shell. 

 Larger or pedicle valve usually much 

 more convex than the brachial; umbo 

 straight or incurved ; median sinus pres- 

 ent or absent. Between the valves is a 

 relatively large and broad pedicle open- 

 ing owing to the rudimentary cardinal 

 areas. Surface with concentric growth lines. Interior with muscle 

 scars radiating from the beak. Lower-Middle Cambric. 



64. K. cingulata Billings. (Fig. 246.) Lower Cambric. 

 Pedicle valve convex, arching over to the incurved and pointed 



beak ; mesial sinus often present. Brachial valve depressed, with 



Fig. 245. Pholidops hamil- 

 tonice, interior, X 8, and exte- 

 rior, X4- (After Hall.) 



Fig. 246. Kutorgina cingulata, ventral, profile and dorsal views, denuded mostly 

 of outer surface. (After Walcott. ) 



elevated but not incurved beak. Surface covered with coarse striae 

 and in older portions with undulations of growth. 

 Vermont, Quebec, Labrador. 



XXVII. Dictyonella Hall. 

 * Subtriangular, biconvex. Pedicle valve with a broad median 

 sinus and acute and arched umbo. Delthyrium closed by a de- 

 pressed plate. Brachial valve with a broad median fold ; median 

 septum high. Exterior surface pitted with quincunx, resembling 

 Irematis. Si 1 uric. 



