360 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



Description. — The body is rotund ellipsoidal with broad, rounded apices, nearly circular in 

 cross-section, its length 1.51 transdiameters at the widest part at the middle. The epicone 

 exceeds the hypocone in size, its length being greater by 0.13 of its own length. It is subhemi- 

 spherical in shape with broad apex. It has a length from the proximal and distal ends of the 

 girdle of 0.27 and 0.77 respectively of the total length of the body, the distal portion consisting 

 of a narrow band making one complete turn around the body. The hypocone is slightly broader 

 than the epicone, somewhat asymmetrical with broad antapex scarcely notched by the distal end 

 of the sulcus. 



The proximal and distal ends of the girdle lie at a distance from the apex of 0.27 and 0.77 

 respectively of the total length of the body, having a displacement of 0.76 transdiameter. It 

 sweeps around the body in a descending left spiral course of two complete turns. The furrow 

 has a width of about 0.08 transdiameter, and is rather deeply impressed, the excavation under- 

 cutting the anterior border and curving gradually out to the posterior one. The anterior 

 flagellar pore opens at the anterior border of the junction of girdle and sulcus, the posterior 

 pore at the posterior border of the distal junction, on the same surface of the body. 



The sulcus makes one complete turn above the anterior flagellar pore, passing around the 

 apex and terminating just below it on the ventral surface near the right side. Below the pore 

 it passes directly backward a short distance before turning to the left and continues its course 

 as a descending spiral, making a complete turn before meeting the girdle, beyond which it 

 descends directly to the antapex. It thus makes two complete turns about the body. It forms 

 a narrow trough throughout its course anterior to the postei'ior flagellar pore, posterior to which 

 it widens to 3.5 times its own width and at the antapex makes a wider flare. The borders are 

 smooth and rounded. 



The nucleus is subspheroidal in shape and located in the left side of the equatorial region. 

 Its axis is 0.5 transdiameter in length. Moniliform chromatin strands follow its longitudinal 

 axis in curxnng lines. 



Small club-shaped pusules open into the anterior and posterior flagellar pores. The cytoplasm 

 is clear and finely granular. Beneath the peripheral layer is a zone of vacuolate structure. The 

 vacuoles appear rounded in optical section (fig. GG, 2) and in surface view (pi. 5, fig. 60) as 

 irregularly shaped vacuoles closely pressed together over the entire surface. These seemed to 

 be filled with a pale rhodonite, pink-colored fluid, the intervening spaces being greenish. Out- 

 side of this zone is a distinct periplast, appearing as a double-contoured wall. In the central 

 part of the body is a large ellipsoidal, greyish food mass and scattered through the cytoplasm 

 a few small oil globules. The color of the protoplasm is a pale glaucous green distributed 

 throughout. A thin-walled, hyaline cyst enclosed the indi^-idual figured. 



Di:mexsioxs. — Length, 70-74^; transdiameter, 45-50/^; transdiameter of 

 nucleus, 16-18/*. 



OccuBEEXCE. — Two individuals were taken on July 5, 1917, with a Xo. 12 

 silk net, in a haul 6 miles off La Jolla, California, from 80 meters to the surface 

 and in a surface temperature of 2T?4 C. Several individuals were taken the 

 following week from approximately the same place and under the same condi- 

 tions. It was met again July 11 in a haul 4 miles off La Jolla with a No. 25 silk 

 net from 80 meters to the surface. 



CoMPARisoxs. — Cochlodinium clnrissimum belongs to the citron group of the 

 subgenus Cochlodivinm, and like C. citron (fig. HH, 12) and C. faurei (fig. 

 GG, 4) its girdle foi-uis two complete turns around the body. The apical loop 

 is not found so fully developed elsewhere in this genus and resembles that 

 structure as developed in Pouchetia, as, for example, in P. suhnigra. 



