KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 367 



torsion of 1.2 turns; color, greenish grey. Length, 56^^. Pacific off La Jolla, 

 California, July, August. 



Description. — The bodj' is of robust habit, subovoidal to ellipsoidal in shape, moderately 

 constricted by the furrows, circular in cross-section, slightly broader anteriorly, its length 1.36 

 transdiameters at the widest part. The epicone and hypocone are subequal in size. The epicene 

 is rounded anteriorly or may have the appearance of a broad flat cone, with blunt apex. It has 

 a length at the proximal and distal ends of the girdle of 0.18 and 0.83 respectively of the total 

 length of the body. Its distal portion forms a narrow band anteriorly, becoming wider and 

 again contracting to a slender point distally. The anterior portion of the hypocone is wider 

 than the corresponding part of the epicone, with its sides rounded posteriorly and the antapex 

 deepl.v notched by the distal end of the sulcus. 



The proximal and distal ends of the girdle lie at a distance from the apex of about 0.18 and 

 0.83 respectively of the total length of the body. It forms a descending left spiral of two 

 complete turns, the first and last parts of its course having a nearly transverse direction for 

 about 1 transdiameter, the remainder of its course forming an angle of 25° to 30° with the 

 transveise plane of the body. The furrow varies slightly in width, its average being about 0.04 

 and 0.06 transdiameter. It is deeply impressed, often constricting the hotly, with the excavation 

 undercutting both borders, either of which may be smooth or with an irregular wavy outline. 



Tiu' sulcus extends anteriorly from the anterior flagellar pore to the left side of the apex in 

 a lightly curved line. After passing the proximal end of the girdle it turns towards the left 

 and sweeps around the body in a descending left spiral which makes slightly more than one turn 

 before meeting the distal end of the girdle, beyond which it follows a straight line to the antapex. 

 Its width is less than half that of the girdle except at the region of the anterior pore and the 

 distal end of the girdle. It expands near the posterior end of the body, deeply notching the 

 antapex. The anterior flagellar pore is found at the proximal end of the girdle, the posterior 

 pore just beyond the distal junction of the girdle and sulcus. 



Th" inicleus is s]jheroidal to ellijjsoidal in shape and is located in the posterior part of the 

 body. It is filled with moniliform chromatin strands. Its axes are about 0.46 and 0.4 trans- 

 diameters in length respectively. 



The cytoplasm is finely granular, but usually very clear and transparent. Small saeldike 

 pusules may be present at either or at both pores. In one individual the posterior pusule was 

 rather short with two subequal diverticula starting from its proximal end. Food bodies are 

 generally present in the cytoplasm, the individual shown in figure 25, i)late 2, having one large 

 }-ellowish mass centroanteriorly, with several green and dark refractive bodies near it. Small 

 blue-green oil droplets were present in the peripheral zone. The general color of the organism 

 is pearl grey and green, a few individuals showing a yellowish green tone. No striae or other 

 markings could be detected on its surface. 



Di^tENSiONS. — Length, 55-60/^; transdiameter, 35-41/^; axes of nucleus, 19^^ 

 and 16/A. 



Occurrence. — A single individual was taken July 20, 1917, with a No. 25 

 net, 6 miles offshore at La Jolla, California, in a haul from 80 metei'S to the 

 surface and in a surface temperature of 20?5 C. It was also found July 24, 

 2.75 miles offshore, and August 17, 0.75 miles offshore, in hauls from 80 meters 

 to the surface and surface temperatures of 21?9 C and 22-5 C. 



CoMPARisoxs. — This species belongs to the subgenus CorJtlodinium, a group 

 showing consideralile s^^^motr^' of form, and stands next to C. clarissimnm 

 (fig. GO, 2) in size and proportion, ])ut the uppermost part of the epicone is 

 mucli smaller, the apical loop of the sulcus less developed, its peripheral plasma 

 less differentiated, and its color slightly different. 



