PLATE IV (continued). 



Fig. 



13. 20. Cytherideis Colwellensis, p. 49 

 13 a. Right valve, outside 

 13 b. Perfect, dorsal aspect 

 13 c. Perfect, posterior aspect 

 20 a. Left valve, outside 

 20 b. Left valve, dorsal aspect 

 20 c. Left valve, hinge-line 



14. Cytheridea 'perforata, p. 44. 



a. Left valve, outside 



b. Left valve, dorsal view 



c. Right valve, hinge-line 



d. Left valve, outside i 



T. p 1 , r Youns 



e. Perfect, dorsal aspect J 



15. Cythere Wetherellii, p. 26. 



Right valve, outside 



16. Cythere plicata, -p. 32. 



Left valve, outside 



. X 



25 ^ 





X 



25 





. X 

 . X 



25 

 25 



Colwell Bay 



X 



25 





. X 



25 . 





X 



25 ^ 





. X 



25 





X 



25 



Colwell Bay 



. X 



25 





X 



25 ' 





. X 



25 



Colwell Bay 



. X 



25 



Colwell Bay 



17, 18. Cythere angulaiopora, p. 34. 

 17. Left valve, outside 



[The ornamentation is not drawn strong enough.] 



18 a. Perfect, dorsal aspect 

 18 b. Perfect, anterior aspect 



\ Large individuals 



X 25 



X 25 

 X 25 



Colwell Bay. 



19. Cythereis cornuta, p. 39. 

 Left valve, outside 



X 25 ColweUBay. 



