131 



Fig. 4. Fig. 5. Fig. 6. Fig. 7. 



Figs. 4 and 5. Ventral and dorsal views of the cast of a 

 more oblate form of C. julia enlarged to correspond with 

 figs. 1 and 2. 



Figs. 6 and 7. Vental and dorsal views of Cryptonella 

 meta, from the Schoharie grit. 



Fig. 4 is given simply to show the dental lamellae of the 

 ventral valve, the delicate impressed line in the centre and 

 a fainter one on each side, described by Prof. Winchell, 

 are not shown in the figure. These marks, however, are 

 shown in figs. 6 and 9, and characterize the ventral valves 

 or casts of this valve in all the known species of the genus. 



Fig. 8. Fig. 9. Fig. 10. Fig. 11. 



In the Fifteenth Report on the State Cabinet, I gave the 

 accompanying fig. 8 of the dorsal valve, and fig. 9 of the 

 interior of a ventral valve. Figures 10 and 11 are dorsal 

 and profile views of Cryptonella eximia, from the Lower 

 Helderberg group, the earliest species of the genus known 

 to me. 



The Genus Cryptonella may be characterised as follows : 



