206 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



Dimensions. — Length, 193/^ to 212/^; transdiameter, 95/^ to 110/*; major and 

 minor axes of nucleus, 42/^ and 26^. 



Occurrence. — The individual figured was taken June 27, 1917, with a No. 

 12 silk net, in a haul 6.1 miles off La Jolla, California, from 120 meters to the 

 surface and in a surface temperature of 20?6 C. It was taken on July 20, 6 

 miles off La Jolla, and on July 27, 4 miles off La Jolla, with a No. 25 silk net, 

 from 80 meters to the surface and in a surface temperature of 21° C. On 

 August 13 it was quite abundant in a haul 0.75 miles off La Jolla from a depth 

 of 83 meters and in a surface temperature of 21 ?9 C, 6 individuals being ob- 

 served in a short examination of this catch. 



Comparisons. — This is one of the largest species of Gjimnodinium thus far 

 described, the length of the longest individual observed, 212/^, being the greatest 

 length on record, the nearest approach to it being G. cucumis with a length of 

 210/*. It is also one of the most highly differentiated species in the genus in 

 its cyto])lasmic structure, reseml^ling in this respect G. pachi/dcniiatnui sp. nov., 

 G. ampJiora sp. nov., and G. ahhreviatum sp. nov. (figs. AA, 5, 6; fig. Z, 7). Like 

 them it is holozoic in nutrition, the presence of numerous green rodlets and 

 masses of refractive bodies indicating a high degree of metabolism. It is one 

 of the most striking, richly colored dinoflagellates found in the La Jolla region, 

 sharing that distinction with G. parhi/dfDiiatuui. which it greatly resembles in 

 color. It belongs to the subgenus Paclnjdinium, with these species, and differs 

 from them in its longer, more attenuate epieone and less displacement of the 

 girdle. 



t) 



Gymnodinium doma sp. nov. 



Plate 5, figure 57 ; text figure X, 31 



Diagnosis. — This is a small species with ovoidal Iwdy, its length 1.43 trans- 

 diameters ; girdle premedian, displaced about twice its own width ; sulcus short 

 on lioth epieone and hy]>ocone; color blue grey. Length, 59/*. Pacific off La 

 Jolla, California, Jidy. 



Description. — The body is ovoidal with broad apices, circular in cross-sectiou, widest anter- 

 iorly, its length 1.43 transdiameters at the widest part, which is at the girdle. The hypoeone 

 exceeds the epicene in size, its length being greater b.y about 0.23 of its own length, though its 

 transdiameter is somewhat less. The epieone is hemispherical in outline with symmetrically 

 rounded apex. It has a length on the left and right sides of 0.33 and 0.45 respectively of the 

 total length of the body. The hypoeone is elongate hemispherical, or eampanulate in outline, 

 flaring at the girdle, tapering slightly posteriorly with broad rounded antapex. 



The girdle is premedian in position, its anterior junction with the sulcus occurring at a 

 distance from the apex of 0.33 of the total length of the body. It passes around the body in a 

 transverse direction for 0.75 of its course, beyond wliich it turns posteriorly and joins the sulcus 

 at an angle of 70° with the main axis of the body. It is displaced about twice its own width. 

 The furrow is wide, about O.Of) transdiameter in width, and is deeply impressed with smooth 

 borders. The sulcus is short, beginning midway of the distance between girdle and apex on 

 the epicene and extending posteriorly for about the same distance on the hypoeone. Its course 



