378 MEMOIRS OF THE UNIVERSITY OP CALIFORNIA 



antapex scarcely notched by the distal end of the snkms. The antapex is somewhat broader 

 and more flattened than the apex. 



The girdle has a distance from the apex at its proximal and distal ends of about 0.33 and 

 0.91 respectively of the total length of the body. It is a descending left spiral of two turns 

 with a displacement of 0.75 transdiaraeter. The first 1.2 transdiameter of its course is in a 

 nearly transverse plane, turning posteriorly with an angle of 30° to 20° from the transverse 

 plane, the latter 0.5 transdiameter again rising to a nearly transverse direction. It meets the 

 sulcus distally at a distance from the antapex of less than 0.1 of the total length of the body. 

 The furrow varies slightly in the width, being widest in the middle, where its width is about 

 0.04 transdiameter, and narrower at its proximal and distal ends, and is deeply impressed, 

 undercutting its anterior lip and sloping gradually out to the posterior one. The body is 

 slightly constricted by the furrow on the left side and on the right the borders are slightly 

 elevated above the surrounding surface. 



The sulcus begins near the apex as a wide, shallow furrow, which passes posteriorly as a 

 descending left spiral of slightly more than one turn. After passing the anterior pore it 

 contracts to less than half its width above, expanding again after passing the posterior pore 

 into a broad, shallow trough, which fades out at the antapex. The anterior and posterior pores 

 are located at the anterior and posterior junctions of the girdle and sulcus respectively. 



The nucleus is elongate ellipsoidal in form, located on the right side of the posterocentral 

 part of the body. It is filled with fine, moniliform chromatin strands. Its ma.ior and minor 

 axes are about 0.6 and 0.27 transdiameter in length respectively. 



A long, slender pusule connects the anterior and posterior flagellar pores, forming a complete 

 channel between the two openings. The cytoplasm is finely granular and a mixture of pearl 

 grey and light glaucous blue in color. The specimen figured was unusually free from oil drop- 

 lets. One large food mass, green and yellow ochre in color, was present in the anterior region. 

 There were two groups of long, slender, tapering, greenish, radial rodlets. one of which was in 

 the anterior part near the food mass and the other in the posterior region. Lying in the 

 periphery, and scattered over the entire body, are irregular splashes of pigment, aster purple 

 in color, the larger masses showing a deeper tone than the smaller, lighter ones. A thin hyaline 

 cyst, slightly larger than the body, enclosed one individual. 



Di>[EXSioxs. — Length, 68-78;^; transdiameter, 52-60/^; axes of nucleus, 

 33-36M and 14/^ ; length of radial rodlets, 12-18/^. 



OccuEREXCE. — The specimen figured was taken July 25, 1917. with a Xo. 

 25 silk net in a haul 11 miles off La Jolla, California, from 80 meters to the 

 surface and in a surface temperatitre of 21-2 C. A second individual was 

 taken August 10 with the same apparatus 1 mile off La Jolla in a haul from 

 50 meters to the surface and in a surface temperature of 21?9 C. 



CoMPAEisoxs. — The most striking feature of this species is its color of 

 irregular, clu-omatophore-like splotches of aster purj^le. This is unlike that 

 of any other species of the genus and finds its counterpart in Giinnwdinium 

 violcscens (pi. 6, fig. 69) and G. liueopiDiicum (pi. 6, fig. 65). No observations 

 of the motility of the pigment were made, imt it is probable that it possesses that 

 characteristic in common with the pigment of G. Uneopiaiiciou and Gyrodinium 

 ocJiraccnm (jdI. 7, fig. 76). 



Coclilodinium radiatum falls in the C. citron groitp of the subgenus CocMo- 

 dinimn, and lies midway between C. virescens (fig. HH, 11) and C. citron (fig. 

 HH, 12) in the amount of torsion of the body as sho^vn in the length of the 

 girdle. 



