296 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



Gyrodinium culeus sp. uov. 



Plate 7, figure 77 : text figure CC, 2 



Diagnosis. — A mediiun sized species with ellipsoidal body, its length 1.71 

 trausdiameters ; girdle a siibniedian. desceuding left spiral, displaced 0.63 trans- 

 diameter; sulcus extending from apex to antapex; color, pearl grey with rose- 

 red pigment granules. Length, 65/*. Pacific off La Jolla, California, August. 



Description. — The body is subellipsoidal in outline, widest posteriorly, with broad apices, its 

 length 1.71 transdiaineters at the widest part, which is near the middle of the hypocone. The 

 hypoeone exceeds the epieone in size, its length being nearly equal but its transdiameter slightly 

 greater than that of the epicene. The epieone is elongate hemispherical in shape, with symmet- 

 rically rounded sides. It is slightly notched at the apex by the proximal end of the sulcus. The 

 right side widens somewhat behind the level of the anterior pore. It has a length on the left 

 and right sides of 0.32 and 0.68 respectively of the total length of the body. The hypocone is 

 elongate hemispherical in shape, slightly wider with sides more convex than those of the epieone. 

 The antapex is smoothly rounded without sulcal notch. 



The girdle is submedian in position. Its proximal end joins the sulcus at a distance from 

 the apex of 0.32 of the total length of the body. It follows a descending left spiral course around 

 the bodj^ and meets the sulcus at a distance from the apex of 0.68 of the total length of the body, 

 its displacement being 0.63 transdiameter. It has a width of about 0.06 transdiameter and is 

 deeply impressed will smooth borders. The sulcus begins in a slight enlargement at the apex 

 and extends posteriorly in an almost straight line to near the antapex. The anterior flagellar 

 pore opens at the proximal junction of the girdle and sulcus, the posterior pore about one width 

 of the girdle below their posterior junction. 



The nucleus is a broadly ellipsoidal body, filled with fine, moniliform chromatin strands with 

 a circular arrangement. It is found in the anterocentral part of the body. Its major and minor 

 axes are about 0.55 and 0.44 trausdiameters in length respectively. 



A small, sacklike pusule opens into the anterior flagellar pore. None was noticeable at the 

 posterior pore. The cytoplasm is finely granular and, in the individual figured, was densely 

 filled with large vacuoles containing a salmon-pink fluid. No other bodies were present. The 

 general color of the cytoplasm is a pearl grey, with a faint tinge of rose red. The latter color 

 was condensed into a group of rose-red granules at the antapex and another group near the left 

 margin of the body, immediately below the girdle. No striae or other surface markings could 

 be detected. 



Dimensions. — Length, 65m ; transdiameter, 38/* ; axes of nucleus, 21/* and 17/*. 



OccuERExcE. — One individual was taken August 8, 1917, 4 miles off La Jolla, 

 California, in a haul from 80 meters to the sui-face and in a surface temperature 

 of 21?9 C. 



CoMPAEisoxs. — The rose-red color of this form is the same as that found in 

 Gymnodinium ruhriim (pi. 8, fig. 86), G. nihricauda (pi. 8, fig. 88), G. liiicdttou 

 (pi. 1, fig. 2), and G. sulcatum (pi. 8, fig. 83). The only Gijrodimum jDreseuting 

 the same coloring is G. rubricaudatum (pi. 10, fig. 116). Near it, however, is 

 the coral red of G. coralUnum (pi. 10, fig. 117) and G. virgatum (pi. 10, fig. 112). 



The only non-striate Gi/rodinlum approaching this species in size and pro- 

 portions is G. dorsum sp. uov. (fig. CC, 19), but this species differs from G. 

 culeus in having less displacement of the girdle, which is also farther posterior. 



