KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 195 



towards the right side of the body and deeply notched by the anterior end of the snlcus. The 

 hypoeone is slightly asymmetrical with the left side more convex than the right. It is bifurcated 

 at the posterior end by the deep excavation of the sulcal notcli which reaches through and cuts 

 the dorsal surface of the body. 



The girdle is submedian in position, its proximal end joining the sulcus at a distance from 

 the apex of 0.4:3 and its distal end 0.53 of the total length of the body. It follows a descending 

 left spiral course around the body, displacing its distal end po.steriorly 0.18 transdiameter. The 

 furrow is wide, about 0.09 transdiameter, and deeply impressed with smooth, overhanging 

 borders. The sulcus extends from the apex to the antapex in a slightly sinuous line, and deeply 

 notches both apices. The trough is narrow and shallow anteriorly, but expanding laterally and 

 sinking deeper into the body posterior to the girdle until it nears the antapex where it reaches 

 through and cuts the dorsal surface, bifurcating the posterior end of the body. The anterior 

 flagellar pore opens at the proximal junction of the girdle and sulcus, the posterior pore some- 

 wliat behind the middle point between the distal junction and the antapex. 



The nucleus is a large, ellipsoidal body in the center of the hypoeone. In the specimen 

 examined its nuclear structure could not be determined with any degree of accuracy. Its major 

 and minor axes are about 0.49 and 0.3 transdiameter rsepectively. A small sacklike pusule 

 opens into the posterior flagellar pore. None was noted at the anterior pore. 



The cytoplasm is coarsely granular, somewhat dense, with closely packed vacuoles filling 

 the entire central part of the body. A mass of minute, highly refractive granules lies in the 

 region of the anterior flagellar pore. The cytoplasm and most of the vacuoles are grey in color, 

 others showing a faint tinge of salmon pink. The surface is covered with longitudinal, equi- 

 distant, blue-green striae, approximately equal in number on both epicone and hypoeone. Minute 

 blue-gi-een spherules are profusely scattered through the peripheral layer between the striae. 



Dimensions. — Length, 112m; transdiameter, 65/*; major and minor axes of 

 nucleus. 32/* and 20/* respectively. 



Occurrence. — A single individual was taken August 17, 1917, with a No. 25 

 net, 0.75 of a mile off La Jolla, California, in a haul from 80 meters to the 

 surface and in a surface temperature of 22?5 C. 



Comparisons. — This species, while not exhibiting the distinct ectoplasmic 

 differentiations of G. dogieli, yet possesses a j)eriplast of firmer consistency than 

 any member outside of the subgenus Paelnjdininm, and it is therefore placed 

 in that group. It stands near G. costatum, differing from it in its proportions 

 and in the contracted shape of the epicone. In the marked asymmetry of its 

 epicone it stands apart from all other species of G ymnodiniian , though the 

 lateral displacement of the apical point in such species as G. luumdus sp. nov., 

 G. agUc sp. nov., and G. vestifici Schiitt (fig. Y, 5, 9, 10) is indicative of as\^n- 

 metrical tendencies. 



Gymnodinium carinatum Schilling 

 Text figure X, 34 



Gymnodinium carinatum Schilling (1891), p. 278, pi. 10, fig. 12. 

 G. carinatum, Mez (1898), p. 216. 



G. carinatum, Lemmermaun (1900), p. 116; (1903), p. 260. 

 G. carinatum, West (1916), fig. 36a. 



Diagnosis. — A minute species with ellipsoidal body, its length 1.5 trausdi- 

 ameters ; girdle without disiDlacement ; sulcus extending from girdle to antapex, 



