PLATE 105. 



Page 



Fig. 1-6. Renssel^ria ovoides. 456 



1. Dorsal valve of a full-grown individual, showing the abrupt inflection at tlie sides. 



2. Profile of a large shell in which the parts are pretty well preserved in all their proportions; 



the dorsal valve being partially exfoliated, and the striae not visible. 



8. Ventral view of the preceding. 



4. Dorsal view of a large specimen, which is unusually contracted at the sides on the lower 



half of the shell. 



5. A partial cast of a ventral valve, showing the form of the mitscular impressions and rostral 



cavity. The forms of the dental plates and teeth are seen on each side, below the beak. 



6. A partial cast of a dorsal v^lve, showing a process reaching from the beak to the muscular 



impressions below. This process is the filling of the foramen, and extends from the cavity 

 of the dorsal valve beneath the bases of the crural supports, coming out at the apex of 

 the beak. 



