KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 263 



The nuek'us is a ratlier large, spheroidal body filled with fine chromatin strands. It is found 

 in the left dorsal side of the liypocone. Its axis is about 0.44 transdiameter in length. 



The cytoplasm is very clear and transparent and without apparent granulations. It is 

 suffused throughout with a glassy, bluish glaucous tint which gives its color to the organism. 

 The anterior half of the body contains a large food mass, irregular ellipsoid in shape and greyish 

 javel green in color. Two smaller, grey, i-efractive bodies were present in the hypocone, and a 

 number of still smaller refractive bodies in the antapieal region near the nucleus. Nutrition is 

 evidently holozoic. The surface is covered with longitudinal, equidistant striae, blue green in 

 color, about 20 across the ventral face of the girdle. The number of these on the hypocone 

 exceeds the number on the epieone by about 0.1. 



Dimensions. — Length, 87/* ; transdiameter, 45/* ; axes of nucleus, 25/*. 



OccuKRENCE. — A single individual was taken June 26, 1917, at La JoUa, 

 California, Avith a ISTo. 12 net, 1 mile offshore, in a haul from 120 meters to the 

 surface and in a surface temperature of 20?6 C. 



CoMPABisoxs. — This form has the glassy, glaucous appearance not uncom- 

 mon throughout the G^Tiinodiniidae, as, for example, in CocModinium vinctum 

 and Erijthropsis extrudens. Gj/mnodintnni gracile sometimes exhibits the same 

 bluish color, but the two species are widely different in their morphological 

 characters. It belongs to the subgenus Lineadinium, but stands rather alone. 

 Its epieone and general form approach that of G. muUilineatum sp. nor. (fig. 

 Y, 18), but its bifid antapex, sparse striae and displaced girdle clearly separate 

 it from that species. 



Gymnodinium triangularis Ticbour 



Text figure BB, 2 

 (hjmnodiniiim triangularis Lebour (1917&), p. 102. fig. 7. 



The form figured by Lebour (1917Z>) as G. tridiKjulnriH is evidently a muti- 

 lated specimen. The posterior j)art of the body is frequently deformed in many 

 of these frail, delicate organisms, as in Poiichetia maxima (pi. 6, fig. 61). This 

 is often the result of the extrusion of a large food mass, and the deformation 

 may last for some time or may close immediately. This process was often 

 followed by us, particularly in Gymnodinium lieterostriatum. 



The form figured l)y Lelwur is subtriangular in shape, truncate posteriorly, 

 with the hypocone greatly exceeding the epieone in size. The sulcus is omitted 

 from the figure, but the longitudinal flagellum arises near the apex (?). The 

 data given are incomxjlete, and, combined with the reasons stated above, would 

 throw this among the doubtful forms until it has been found again. The point 

 of origin of what is apparently the longitudinal flagellum raises the question of 

 the orientation of this organism, which may possibly be inverted. 



