198 University of ('ah'fo)-uia Publications in Zoology. [Vol.8 



Steiniella, however, has its epitheca also of the same skeletal 

 constitution as that of Gonyaulax and should on this ground be 

 included therein. The fact that the apex (region of the closing 

 platelet) is carried over on the dorsal face scarcely suffices as a 

 generic character, as it is almost realized in some species of 

 Gonyaulax, as for example in G. alaskensis and G. hyalina, and 

 the gap between the two genera is practically obliterated. Recog- 

 nizing the fundamental identity of the skeletal formula in these 

 two genera and finding it difficult to apply consistently any set 

 of morphological distinctions between the two as the number 

 of species ascribed to them has increased, I feel constrained to 

 include titeiniella Schiitt (1895) in the older genus Gonyaulax, 

 according it therein only a subgeneric status. 



The differences between the valid species of Steiniella {S. 

 fragilis, S. mitra, and 8. infiaia) and Gonyaulax are no greater, 

 if indeed as great, as those now found between species within 

 Gonyaulax itself. A marked tendency to fall to pieces on the 

 part of the theca, the predominance of vermiculate-linear mark- 

 ings, and an elongated apex overlapping the dorsal edge of the 

 anterior end of the body are the only available characters upon 

 which to found the genus Steiniella, and no one of them affords an 

 adequate basis for separation since they are all to be found in 

 varying degrees within Gonyaulax itself. They are, moreover, 

 purely superficial characters such as are subject to gteat modi- 

 fications in many of the larger genera of the dinoflagellates. 



The species of Steiniella thus far described which should be 

 transferred to Gonyaulax are the following: 



Gonyaulax {Steiniella) fragilis Schiitt. See Schiitt (1895). 



G. (Steiniella) mitra (Schiitt). See Schiitt (1895). 



G. {Steiniella) in fata (Kofoid). See Kofoid (1907a). 



Certain other species have been described in the genus Stein- 

 iella which have previously been otherwise assigned. Steiniella{ ?) 

 punctata described by Cleve (1900a) was assigned by me 

 (1907a) to the new genus Murray ella, while Cleve 's (1903) 

 Steiniella { ?) complanata was in the same paper referred by me 

 to another new genus Centrodinium. Steiniella cornuta de- 

 scribed by Karsten (1907) is identical with the larger forms of 



