KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 191 



can not be accepted even with reservations until the subject has received further 

 investigation. It is highly probalile that this species has the equipment of 

 flagella normal to the Dinoflagellata. 



G. 'biciliatum belongs to tlie siibgenus Gymnodininm. 



CoMPABisoxs. — In size, proportions, and color this species approaches G. 

 togoriense Klebs and G. aeruguiosum ,tliougl\ not the figure selected by Schilling 

 (1913) as typical. It is some^Yhat smaller than the average, 22. 2/^, and smaller 

 than G. aeruginoHum, which Schilling (1913) states to have a length of 33-34/^, 

 and is also relativel.y stouter. Cyst formation has some features in common 

 in the two species, but the rigid irregularly spinose cyst of Ohno's species is 

 ai^parently different from the imperfectly known cyst of G. aeniginosum. Its 

 dimensions are very close (22. 2i" by 16.9m) to those of Klebs 's (1912) species 

 (22j^ by 11m-), and the two may prove on full examination of chromatophores 

 and cysts to be identical. If so Ohno's (1911) name has priority over that of 

 Klebs (1912). 



Gymnodinium bicorne sp. nov. 



Plate 2, figure 14 ; text figure BB, 10 



Diagnosis. — This is a small species with subreniform body, its length 2.86 

 dorsoventral diameters; girdle submedian, displaced twice its own width; 

 sulcus extending from near apex to antapex ; color yellowish grey. Length, 63?^. 

 Pacific off La Jolla, California, July. 



Description. — The body is slender ellipsoidal, with broad apices, subreniform in lateral view, 

 its dorsoventral diameter slightly greater than its transdiameter, its length 2.86 dorsoventral 

 diameters at its widest part. The epicone and hypocone are subequal in length. The epieone 

 is rounded conical in ventral view with broad apex ; in lateral view the dorsal side is convex, the 

 ventral concave posteriorly, convex anteriorly. It has a length on the left and right sides of 

 0.42 and 0.54 of the total length of the body respectively. The hypocone is somewhat narrower 

 posteriorly than the corresponding part of the epicone. The antapex is rounded without sulcal 

 notch. 



The girdle is submedian in position, with a distance from the apex at its proximal and distal 

 ends of 0.42 and 0.54 of the total length of the body respectively. The furrow has a width of 

 about 0.09 transdiameter and is deeply impressed with smoothly rounded borders. Its course 

 is that of a descending left spiral, with its di.stal end displaced posteriorly about twice its own 

 width. 



The sulcus is a narrow trough extending from near th(> apex to tlie antapex in an almost 

 straight line. Its greatest width is found in the intercingular area, becoming narrower on the 

 epicone and hypocone and fading out near both apices. The anterior flagellar pore opens at the 

 proximal junction of the girdle and sulcus, the posterior pore a short distance below the distal one. 



The nucleus is an ellipsoidal body lying in the central plane with its major axis parallel to 

 the major axis of the body. It is filled with moniliform chromatin strands. Its major and 

 minor axes are about 0.86 and 0.36 transdiameter in length respectively. 



The plasma is finely granular and contains numerous small green granules and dark refractive 

 bodies. An irregular, saeklike pusule opens into the anterior flagellar pore. The color of the 

 cytoplasm is pearl grey with yellow s])lashes through it that may be chromatophores. This 



