(Sonderabdruck aus dem »Zoologisoheii Anzeiger* Bd. XXXII. Nr, 7 

 vom 1. Oktober 1907.) 



The plates of Ceratium with a note on the unity of the genus. 



By Prof. Charles Atwood Kofoid. 



(Zoological Laboratory, University of California, Berkeley.) 



(With 8 figures.) 



In the course of the preparation of an account of this genus as i 



occurs in the plankton of the Pacific off San Diego I have had occasio: 



to determine the plates of the theca and find my results at varianc 



with those hitherto reported. This has led me to verify, in most parti 



culars, my conclusions here presented, on a large number of individuals 



representing at least sixteen species of Ceratium including represents 



tives of the genera Ceratium sensu aivict Sb,Amphiceratium, Biceratiw. 



and Poroceratium of Vanhoef fen (1896) and has therefore enabled m 



to reach conclusions regarding the validity of this proposed dismembei 



meat of the genus Ceratmm. 



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