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 



e. Perfect, dorsal aspect 



15. Cy there W ether ellii, p. 26. 



Right valve, outside 



16. Cythere plicata, p. 32. 



Left valve, outside 



/ Younc 



X 



25 - 





X 



25 





X 

 X 



25 

 25 



Colwell Bay 



X 



25 

 25 





X 





X 



25 s 





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 



19. Cythereis cornuta, p. 39. 

 Left valve, outside 



Large individuals 



x 25 



x 25 

 X 25 



Colwell Bay. 



X 25 Colwell Bay. 



