324 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



The nucleus is ellipsoidal in shape and located in the anterocentral region. Large, moniliform 

 chromatin strands traverse its longer axis. Its major and minor axes are about 0.5 and 0.4 

 transdiameter in length respectively. 



A large sacklike pusule opens into each flagellar pore. The cytoplasm is granular and often 

 contains a large, reddish-brown food mass, with niimerous blue-green and small refractive 

 spherules. These latter inclusions indicate a holozoie mode of nutrition. Striations and other 

 surface markings could not be detected. The general color of the organism is dilute prirauline 

 yellow mixed with pearl grey and orange, diffused throughout the cytoplasm. 



DiiMEXSioxs. — Length, 45-74m; transdiameter, 3J— 60/^; axes of nucleus, 

 29-33/x and 23-24^. 



OccrERExCE. — The first individual was taken May 31, 1904, in a surface haul 

 9 miles off La Jolla, California. On June 24, 1917, it was foimd in the surface 

 haul taken at the end of the pier at the Biological Station at La Jolla. It was 

 also taken August 10 1 mile offshore in a haul from 50 meters to the surface 

 and on the 15th 0.75 mile offshore in a haul from 83 meters to the surface. 



CoMPAEisoNS. — This species is near G. ovum (Schiitt) ( fig. CC, 8), but is 

 large with relatively nmch less displacement of the girdle, more s}^nmetrical 

 hypocone, and shorter sulcus. 



Gyrodinium ovum (Schiitt) 

 Text figure CC, 8 



Gymnodinium ovum Schiitt (1895), pi. 25, fig. 23. 

 G. ovum, Calkins (1901), p. 118, fig. 64 A. 



Diagnosis. — A small species with ellipsoidal body, its length 1.4 transdiam- 

 eters; girdle a descending left spiral, displaced 0.6 transdiameter; sulcus ex- 

 tending from girdle to antapex; color (0- Length, 28m. Atlantic ( ?) or Bay 

 of Naples. 



Description. — The body is broadly ellipsoidal with broad, rounded apices, its length 1.4 

 transdianieters at the widest part, which is at the middle. The epieone exceeds the hypocone in 

 size, its length being greater by 0.11 of its own length. It is elongate, subhemispherical in shape, 

 with broad, rounded apex. It has a length on the left and right sides of 0.32 and 0.68 respec- 

 tively of the total length of the body. The hypocone is slightly less symmetrical than the epieone 

 and notched on the left side of the antapical region by the distal end of the sulcus. 



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

 apex of 0.32, its distal end 0.68 respectively of the total length of the body, forming a descending 

 left spiral displaced 0.6 transdiameter. The furrow has a width of about 0.12 transdiameter 

 and is rather shallow. The sulcus begins at the girdle and extends posteriorly in a sinuous line 

 to the antapex. The flagellar ])ores were not figured by Schiitt, though lie shows the distal ends 

 of both the transverse and longitudinal flagella. 



The nucleus is an ellipsoidal body filled with coarse chromatin strands and lying in the right 

 central part of the body. Its major and minor axes are about 0.62 and 0.37 transdiameter in 

 length respectively. 



The cytoplasm is filled with small spherules and contains besides these, vacuoles, and one 

 large, spheroidal, brownish food mass, evidence of a holozoie mode of nutrition. The periplast 

 of the body is double contoured in Schiitt 's figure. Color ? 



