KOPOID AND SWEZY: UNARMORED DINOFLAGELLATA 325 



Dimensions. — Length, 28/'-; transdiameter, 20^; axes of nucleus, about 10/* 

 and 6m. 



Occurrence. — Figured by Scliiitt (1895) from material of the Plankton 

 Expedition from the Atlantic or Bay of Naples. 



Synonymy. — The name Gymnodinium ovum as applied to this species by 

 Schlitt is now inapplicable, as the organism presents the Gyrodinium ij^Q of 

 girdle. 



Comparisons. — This species belongs with two other rather small, broadly 

 ellipsoidal, non-striate marine species, G. capsuhitam s]). nov. and G. foUaceum 

 nom. sp. nov. (tigs. CC, 14, 18). It is smaller than either of these, has relatively 

 more displacement of the girdle and greater antapical asjTnmetry. It lacks 

 the apical point found in G. foliaceiim. 



Gyrodinium parvulum (Schiitt) 



Text figure CC, 4 

 Gymnodinium parvidum Schiitt (1895), pi. 25, fig. 84. 



Diagnosis.- — A minute species with subovoidal body, its length 2.2 transdi- 

 ameters; girdle a descending left spiral, displaced 0.88 transdiameter; sulcus 

 ( ?). Length, 33/x. Atlantic ( ?) or Bay of Naples. 



Description. — The body is subovoidal, widest anteriorly and tapering at both ends, its length 

 2.2 transdiaraeters at the widest part, which is at the girdle. The hypoeone exceeds the epicone 

 in size, being nearly three times as large. The epicone is short, conical (90°) anteriorly with a 

 blunt apex. Its length on the left and right sides is 0.20 and 0.36 respectively of the total length 

 of the body. The hypoeone is more tapering and slightly narrower at the antapex, which is 

 without sulcal notch. 



The girdle begins at a distance from the apex of 0.2 of the total length of the body. It 

 follows a descending left spiral course around the body and terminates at a distance from the 

 apex of about 0.4 of the total length of the body. The furrow is wide, about 0.2.3 transdiameter, 

 and deeply impressed with overhanging borders. The .sulcus and flagella are not shown in 

 Schiitt 's (1S95) figure. 



The nucleus is an ellipsoidal body found in tlie anterodorsal part of the organism. Its major 

 and minor axes are about 0.8 and 0.4 transdiameter in length respectively. It is densely filled 

 with coarse chromatin strands. Two large brownish food masses occupy the posterior part of 

 the body. The remainder of the cytoplasm is thickly strewn with vacuoles of varying sizes. 



Dimensions. — I^ength, olV; transdiameter, 15m; axes of nucleus, about 12m 



and 6m. 



Occurrence. — A single specimen of this species has been recorded by Schiitt 

 (1895) from collections made liy the Plankton Expedition from the Atlantic 

 or the Bay of Naples. 



ToiMFARisoNS.— This species is nearest G. pusillnm (Schilling and G. hyali- 

 mim (Schilling), both fresh- water species of smaller size and relatively larger 

 epicone. 



