UNIVERSITY OF CALIFORNIA PUBLICATIONS 



ZOOLOGY 



Vol. 6, No. 8, pp. 177-187 May 26, 1910 



A REVISION OF THE GENUS CERATO- 



COEYS, BASED ON SKELETAL 



MORPHOLOGY. 



BY 



CHARLES ATWOOD KOFOH). 



INTRODUCTION. 



The skeletal plates of the thecal wall of the Dinoflagellates 

 are hard structures of definite shapes, numbers and relationships 

 in the various genera of this subclass of Protozoa. They are 

 subject to modifications in form and size due to a slight extent 

 to growth and to age, and, in certain genera, as in Gonyaulax, 

 to some interspecific differences in number, while in Pyrophacus 

 considerable variation occurs within the species in the number 

 of the plates. In the main, however, the morphology of the 

 plates in this group is remarkably constant and affords a must 

 satisfactory basis for classification and determination of relation- 

 ships, with a definiteness and certainty rarely attainable among 

 unicellular organisms. 



Superficial resemblance to other genera in form and in organs 

 of flotation on the part of the majority of the species of the 

 genus Ceratocorys has hitherto hidden their true affinities which 

 rest upon their skeletal morphology. 



The Dinoflagellate genus of semi-tropical and tropical seas 

 has been a source of great confusion to those who have found its 

 representatives,»with the result that it is now well-nigh impos- 

 sible to determine from the literature its content of species or to 



