Report of ihk State Geologist. 



563 



Discinolepis. Waagen. 1885. 



Shell of wry small size with two unequal valves, which are 



very flat, Leaving scarcely any room for the animal bet u een them. 



The pedicle-valve depressed 



convex, the apex only being a 

 little elevated and removed 

 from tlic margin towards the 



median part of the valve. The 

 posterior margin of the valve 

 near the apex is broadly 



' • After Waagen. 



notched by a Cu'i'\) incision Fig. ->.->i;.- Pedicle-valve. Fig. 257— Brachial- 



reaching to the beak. 



The brachial valve is similar in shape to the other, with a 

 slightly elevated eccentric apex, but without an incision. 



The surface in both valves is either smooth or finely granulose. 



Type, Discinolepis grcmulata, Waagen. Cambrian (India). 



Paterina, Beecher. 1891. 



Valves semi-elliptical in outline, subequal, the pedicle-valve 

 being slightly the more 

 elevated. Hinge line equal 

 to the greatest width of the 

 shell, without cardinal area. 

 Pedicle passage not limited FlG 25S _ Paterina La>radorua. (Walcott.) 

 except by the posterior margins of the valves. 



External surface covered with concentric lines terminating 

 abruptly on the cardinal margin. Shell substance corneous. 



Type, P.aterina Zabradorica, Billings (sp.). Cambrian. Only a 

 single species of the genus is known. 



Kutorgina, Billings. 1861. 

 (Plate 4, Figs. 11-13.) 



Shells inequivalve, transverse or elongated. Hinge-line nearly 

 equaling the greatest width of the shell. Pedicle- valve convex, 

 greatly elevated at the beak, which is more or less incurved. Car- 

 dinal area very narrow, and divided by a wide pedicle-fissure. 

 Brachial valve flat or slightly convex, beak marginal. Cardinal 

 area very feebly developed. The posterior portion of the valves 



115 



