KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 387 



its eoiii'se, its course proximally and distally having a nearly transverse direction. The furrow 

 lias a width of about 0.05 transdiameter, but is obscured throughout most of its course by the 

 rotundity of its borders. It is deeply impressed, often constricting the body to about 0.63 

 transdiameter, and, with the sulcus, throwing the right and left sides of the body into four 

 nearly alternating rounded lobes. 



The sulcus usually invades the epicone in an apical loop that may fade out before reaching 

 the apex or may notch the left side below the apex. After i)assing the proximal end of the 

 girdle it turns to the left in a descending spiral of about 0.9 turn, meeting the girdle distally 

 about 0.24 of the total length of the body from the antapex. Beyond the distal junction it 

 turns slightly towards the right, broadening and often notching the right side of the antapex. 

 The anterior flagellar pore opens at the proximal junction of the girdle and sulcus, and the 

 posterior pore somewhat below the distal one. 



The nucleus is a large, spheroidal body filled with coarse, moniliform chromatin strands. 

 It is located somewhat posterior to the midplane of the body, on the left side. Its axis is about 

 0.44 transdiameter in length. 



In all the individuals of this species observed the pusules were united at their extremities, 

 forming a long tubular canal between the two flagellar pores. The cytoplasm is clear and 

 transparent, often with no trace of granulation. Food bodies are usually present as well as 

 oil globules, refractive bodies and minute blue-green granules scattered through the peripheral 

 zone. The color of the organism is a mixture of pearl grey and green, with a trace of orange 

 peripherally, varying to light turtle green throughout. 



Di^rENSiONS. — Length, 52/^; transdiameter, 36-45/*; axis of nucleus, 15-24/*. 



Occurrence. — The first specimen observed was talven July 11, 1917, with a 

 No. 25 net, 4 miles off La Jolla, California, in a haitl from 80 meters to the 

 surface in a surface temperature of 19-7 C. It was later obsej'ved in most 

 of the hauls made from August 3 to 20, 0.75 to 6.5 miles offshore, from 60 to 80 

 meters depth and in surface temperatures varving from 19-7 C to 22-4 C. 



Comparisons. — This species is distinct in the genus Cochlodinium in the 

 amount of con.striction of the body by the girdle and sidcus, the constriction 

 occurring throughout the entire length of both furrows, with the greatest de- 

 pression along the sulcus. The latter feature is common in the species of the 

 subgenus GlypJiodinmm, without, however, showing a corresponding constric- 

 tion of the girdle. 



Cocltlodiitiion virescois belongs in the C. citron group of the sul)genus 

 CocModi)iin})i, and lies midway between C. lebourae (fig. HH, 7) and C. radi- 

 utum (fig. GG, 12). 



Cochlodinium volutum sp. nov. 



Plate 10, figure 108; text figure GG, 1 



Diagnosis. — A medium sized species with obovoidal l)ody, its hnigth 1.46 

 transdiameters ; girdle a descending left spiral of 1.5 turns, displaced 0.82 trans- 

 diameter: sulcus with torsion of 0.5 turn; surface coarsely striate; color, yellow 

 green. Length, 60/*. Pacific off La Jolla, (\tlifornia, August. 



Description. — The body is obovoidal in shajjc, nearly circular in cross-section, broadly 

 rounded anteriorly and contracting posteriorly, its length 1.46 transdiameters at the widest 



