KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 193 



finlike extension wliich covers about 0.7 of the width of the girdle. The transverse flagellum 

 traverses nearly its entire length. The sulcus does not invade the epieone. On the hypocone it 

 sinks through the body to the dorsal surface, dividing the hypocone into two subequal extensions 

 or flaps (text figure AA, 3). The anterior flagellar pore opens at the proximal end of the girdle, 

 the posterior pore slightly below the distal end. 



The nucleus is an ellipsoidal body located in the central part of the organism, with its long 

 axis lying in a dorsoventral plane. Its major and minor axes are about 0.39 and 0.24 dorso- 

 ventral diameter respectively. 



The cytoplasm is unusually clear and transparent, the granulations being too fine to be easily 

 detected. The ectoplasm is not marked off by a clear-cut line as in G. dogieli, yet it seems to 

 have a slightly different consistency from that of the endoplasm and is more homogeneous. Below 

 this layer in the epieone is a zone filled with small vacuoles. The remainder of the cytoplasm 

 showed no cell inclusions. The surface of the hypocone is marked by a few lines, three on one 

 face, which fade out near the girdle and the antapex. On the epieone these are more numerous 

 and are shorter, being radially arranged around the margin in lateral view. The color of the 

 organism is pinkish grey, deeper on the epieone and through the girdle region, though this latter 

 may be due solely to the greater thickness of the body at that plane. 



Dimensions. — Length, 125/^; transdiameter at girdle, 67/*; dorsoventral 

 diameter, 109/*; axes of niieletis, 60/* and 30/*. 



OccrRREXCE. — This was found August 6, 1917, in a havd with a Xo. 25 silk 

 net, 4 miles off La Jolla, California, in a haul fi'om 60 meters to the surface and 

 in a surface temperature of 21 ?2 C. 



Comparisons. — This organism is a baffling one in attempting to trace out 

 its affinities and eA'en some details of its structure. Owing to its peculiar shape 

 and delicacy of organization a camera drawing cotild not be obtained of the 

 ventral view, the figure given in text figure A A, 3, being made free-hand and 

 its measurements checked up with the camera sketch afterwards. In ventral 

 view it greatly resembles a Peridiniiim escaped from its theca, but a lateral 

 view serves only to emphasize the very great differences between it and any 

 known Peridinium. In its lateral compression it recalls Aiiiphidimum sidcafio)! 

 sp. nov. (fig. L, 26), but differs greatly in all other details of its structure from 

 that species. Its internal cytoplasmic organization is relatively simple, its 

 thickened periplast, however, placing it in the subgenus PacJiydinium. In its 

 coloring it is not unlike G. ahhreviatii iii sp. nov. (fig. Z, 7) in the same subgenus. 



Gymnodinium bogoriense Klebs 



Text figure X, 10 



Gymnodinium bogonense Klebs (1912), pp. 397, 419, 439, fig. 7c, d. 

 G. hogoriense, Cavers (1913), p. 182, fig. 9,. 

 G. bogoriense, Pascher (1916), p. 127. 



Di.\GN()Sis. — A minute species with ovoidal, dorso\'entrally fiattened body, 

 its length 1.3 transdiameters; girdle without (lis])laceiuent ; sulcus extending 

 from girdle to antapex. Length, 23/*. Fresh-water ponds in the Botanical 

 Garden at Buitenzorg, Java. 



