304 University of California Publications. [Zoology 



Ceratium macroceros deflexum, subsp. no v. 



PI. 24, figs. 13-15. 



This is a warm water subspecies of C. macroceros with mod- 

 erate postindentation, but dififering from the type in the marked 

 ventral deflection of the antapicals in their proximal regions. As 

 a result of this position, the antapicals. seen from either face, 

 approach a course subparallel to the apical horn and the distance 

 between them is considerably narrowed as compared wath the dis- 

 tance in C. macroceros. In extreme cases the dorso-ventral dis- 

 tance of this ventral deflection exceeds one transdiameter. The 

 postindentation of this subspecies is nearly equal to that in the 

 typical C. macroceros. 



Length, 300-420/x : transdiameter, 52-6'2/ji ; antapical angle, 

 0°-16°. 



Occasionally taken in plankton of tropical character at San 

 Diego. 



Ceratium mollis, s]). no v. 



PI. 27, fig. 26. 



Ceratium tripos fagellifera forma angusta (in part), Karsten 

 (:06), Taf. 22, Fig. 33b. 



A small species of delicate habit with all three horns greatly 

 elongated and subparallel, rounded tips and slight postindenta- 

 tion. The midbody is small, rotund, with erect apical horn 6-12 

 transdiameters in length. The hypotheca is low, with slight post- 

 indentation, not abruptly delimited from the bases of the antap- 

 icals, often with small fin. The postobliquity is rather steep, 

 30°-50°. The major flexures of the antapicals are completed 

 within 2 transdiameters of their bases. Their course beyond the 

 flexure is approximately parallel to that of the apical at a dis- 

 tance from it of 1.5-2 rarely 2.5 transdiameters. They are 

 delicate and somewhat flexible, exhibiting considerable range of 

 curvature, sinuosities and undulations. Their tips are broadly 

 rounded with terminal pore open or obscure. Thecal wall is 

 hyaline and structureless. 



The species differs from Schroder's ('00) C. tripos var. ma- 

 croceros forma longissima, which is probably a valid species, 0. 



