(>. No clear space on each side ol striate ar< 



1 imu/ans, I 



7. \rc.i with radiating, somewhat undulate striae. 



1 vcrmiculatus* Temp. 



\iva without vermiculate design 



9. — Area elliptic, with short parallel striae near its margins only. 

 Rays [6 to 20. C. Thuretii^ Breb. 



10.— Area circular, or oval, or sub-quadrate. Kays more 



numerous (11. 



1 1. Central portion of Area, with a double T marking. 



( '. bifurcates^ A. S. 

 1 j. No double T mark on Area ( 13). 

 13. — Striae in part parallel horizontally (15). 

 14.- -Striae all radial (21). 

 15. — A circlet (17). 

 16. — No circlet (19). 



17. — Striae short, not reaching the circlet. C. Weissflogii^ Deby. 

 18. — Striae Ion-, reaching the circlet. C. tat Hiatus, A. s. 



19. — Area clepsydrate, with central dumb-bell marking. 



C. tacnioides, Deby. 



20. — No clepsydrate Area nor dumb-bell marking. 



C. ecclesianuSy (ire v. 



21. — Valves, with small, terminal, sub-globular buttons. 



C. vitricavuS) Brum 



* An examination of tin- original specimen of this Diatom, which I have 

 been able t<> make through the kindness <>f M. Tempere, shows that the Rays 

 are indistinctly, though clearly moniliform. I have added a new description 

 of thi> form in the descriptions <>f " N<u Species," so as to render it easier 

 of identification. 



t Probably C. ttmu/ans, Greg., 1- only a variety of C. Thuretii t Breb. 



