322 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



Dimensions. — Length, 110-123m; transdiameter, 45-55/*; axis of nucleus, 

 21-22/*. 



OccuERExCE.- — Two individuals were taken July 12, 1917, 6 miles off La 

 Jolla, California, with a No. 25 net, in a haul from 80 meters to the surface and 

 in a surface temperature of 20° C. The following day it was observed in a 

 haiil taken with the same apparatus 1.25 miles offshore and from 50 meters to 

 the surface. On July 20 it was taken in a haul 6 miles offshore and on July 27 

 at 4 miles off La Jolla. These were taken with the same apparatus, from 80 

 meters to the surface and in surface temperature of 20?5 C and 21?4 C respec- 

 tively. It was fairly abundant in this material, seven individuals being observed 

 in a short examination of the last haul. 



AcTn'iTiES. — These organisms are rather slow in their movements, moving 

 around in large clockwise circles with anticlockwise rotation, changing the 

 direction by a sudden jerk from right to left, sometimes turning in this manner 

 fully 90° or slightly more, and continuing in a new s])iral. 



Comparisons. — The most remarkable feature of this organism is the amoe- 

 boid activity of the pigment, resembling, in this respect, Gymnodinium punicum, 

 and foreshadowing the condition established in Pouclietia and Erytliropsis. 

 Other species, as Gijrodinium macnlatnm, show the presence of mobile pigment, 

 liut this is less active in these species in its movements. 



In its type of structure and proportions this species stands near G. spirale 

 (fig. DD, 14). The latter, however, shows a total lack of pigmentation. In 

 its girdle arrangement it stands near the border line between Gi/rodiniian and 

 Coclilodi)num. The greater amount of torsion of the sulcus occurs posteriorly 

 to the intercingular space as contrasted with its occurrence in the intercingular 

 space in CocModinium. It stands near G. contortum (Schiitt) (fig. CC, 22) of 

 the subgenus Laevigella in the wide displacement and overhang of its girdle, 

 resulting from the torsion of the intercingular sulcus. 



The motility of its yellow-ochre pigment finds its parallel in Gi/nnwdiiiium 

 lineopunicum and in the amoeboid-pigment masses of the more highly special- 

 ized genera, Pouchetia and Erytliropsis. In all of these, however, the pigment 

 shows some shade of red or black, this species being distinct in the possession 

 of a yellow-ochre pigment. 



Gyrodinium ovatum (Gourret) 



Text figure EE 7 



Gymnodinium avafuni Gourret (1883), p. 88, pi. 1, fig. 22. 



Diagnosis.- — A small species with fusiform body, its length 2.88 transdiam- 

 eters; girdle a descending left spiral, displaced 0.92 transdiameter; sulcu's 

 extends from the girdle to the antapex; color, yellow. Length (?). Gulf of 

 Marseilles, France. 



