246 MEMOIRS OP THE UNIVERSITY OF CALIFORNIA 



Dimensions. — Length, 110m ; transdiameter, 70m; axes of nucleus, 36^ and 23m. 



Occurrence. — This species is represented by one individual taken August 

 6. 1917. with a No. 25 silk net 4 miles ofE La Jolla, California, in a haul from 

 60 meters to the surface and in a surface temperature of 21-2 C. 



Comparisons. — This species is unique in its coloring in the genus Gymno- 

 diniiou. In its surface structure it recalls the conditions fovmd in .1. galhauiiiit, 

 the surface being more irregular, however, with its high, rolling ridges, than 

 the latter species. Amphidininni cuciirbifa and Eri/fhyopsis scarlatina also 

 show the same tendency. It belongs in the subgenus Pachijdinium, and repre- 

 sents tlie extreme form of sparse striation, with no near relations. The nearest 

 related species are Gyynnodinmm coendcum and G. wilczeJii Pouchet (fig. Z, 

 4, 8). but color and proportions clearly separate these from G. pnniccum. 



Gymnodinium pyrocystis Jorgensen 



Gymnodinium pyrocystis Jorgensen (1912), p. 10. 



Dl\gnosis. — A large species, stout, its length 1.6 transdiameters ; girdle 

 placed far anteriorly with the ends on the ventral side bent posteriorly ; color- 

 less. Length, 200m. Xorth Sea, September, November. 



Description'. — The body is large, stout, its length about 1.6 transdiameters. The epicone is 

 smaU, about 0.2 of the length of the hypoeone on the dorsal side. It is subconieal with apex 

 blunt or truncate. The hypoeone is large and broadly rounded, often broader and thicker at the 

 posterior end, truncate or notched with broadly round lobes. 



The girdle lies far anteriorly on tlie dorsjil side, both ends curving posteriorly on the ventral 

 side. The sulcus extends from the region of the girdle to the antapex or passes around towards 

 the dorsal side. The nucleus is nearly spherical and is centrally located. The cytopla.sm 

 contains an irregular central mass from which strands pass outward to the periphery where they 

 join. It is filled with numerous spherules of varying size, the largest of which are found in the 

 region of the girdle and at the apices. 



DiiNj ENSiONS. — Length, 50-200m ; transdiameter, 30-150m. 



Occurrence. — This species has been described without a figiu'e by Jorgensen 

 (1912) from the North Sea in September and November. He also records it 

 as moderately abimdant along the west coast of Norway in autumn. 



Comparisons. — This species appears to lie near G. fidgens (fig. X, 30) and 

 not far from the larger forms of AmpJiidiiiiiou such as A. vasculum. 



Gymnodinium radiatum sp. nov. 



Text figure Z, 9 



Dlagnosis. — A medimn sized species with broadly ellipsoidal body in ventral 

 view, slightly flattened dorsoventrally, its length 1.26 transdiameters; girdle 

 slighth' premediau, displaced about twice its own width; sulcus short on epicone, 

 extending to near antai:)ex on h^i^ocone; surface very finely striate. Length, 

 86m. Pacific off La Jolla, California, June. 



