302 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



CoMPARisoxs. — Levander (1894o) describes the long gi-eenish rodlets in his 

 figures as chromatoxAores. Such structures are frequently met A\T.th in the 

 G}^uuodiuiidae, as in Gi/mnodiiiiinn dogieJi (pi. 3, fig. 3-t) and G. pachyder- 

 matum (pi. 8, fig. 32), and, with a shorter length, in many others. These are 

 probably metabolic in origin. On the dissolution of the cytoplasm they dis- 

 a]3pear, as do fluid-filled vacuoles, and our own observations lead us to believe 

 that such is their structure, and that their function is concerned with the 

 metabolism of the cell in other relations than as chromatophores. 



Gyrodinium flavescens sp. nov. 



Plate 4, figure 39 ; text figure CC, 16 



Diagnosis. — A small species with slightly asymmetrical, subovoidal body, 

 its length 1.85 transdiameters ; girdle a descending left spiral, displaced 0.81 

 transdiameter, with overhang of al)out 0.4 transdiameter ; sulcus extending from 

 near apex to antapex, with torsion of 0.4 transdiameter; color, aniline yellow. 

 Length, 50/^. Pacific off La Jolla, California, August. 



Description. — The body is subovoidal and somewhat asymmetrical, its left dorsal side beiug 

 convex and the right ventral slightly concave. In cross-section the body is nearly circular. It 

 is widest posteriorly and its length is 1.85 transdiameters at the widest part. The length of the 

 epicone exceeds that of the hypocone by 0.2.5 of itself. The epicoue is convex on the right side 

 and slightly concave on the left side with broad, rounded apex. It has a length on the left and 

 right sides of 0.36 and 0.8 respectively of the total length of the body. The hypocone is hemi- 

 spherical in shape, somewhat wider than the epicone and slightly notched by the distal end of 

 the sulcus. 



The proximal end of the girdle joins the sulcus at a distance from the apex of 0.36 of the 

 total length of the body. It passes around the body in a descending left spiral, meeting the 

 sulcus at 0.8 of the total length of the body from the apex, with a displacement of 0.81 trans- 

 diameter and an overhang of about 0.4 transdiameter. The furrow has a width of about 0.09 

 transdiameter and is deeply impressed, with smooth, rounded borders. The sulcus begins mid- 

 way between the anterior flagellar pore and the apex. It extends posteriorly in a sigmoid curve 

 with a torsion of about 0.35 to the antapex. Its width is about half that of the girdle, becoming 

 narrower in front of the anterior flagellar pore and beyond the posterior pore. The anterior 

 flagellar pore opens at the anterior junction of the girdle and sulcus, the posterior pore near the 

 antapex. 



The nucleus is a long, sausage-shaped body found in the left side. Its unusual length may, 

 perhaps, be due to the oncoming of division. It was filled with long, moniliform chromatin 

 strands lying in its long axis. Its- axes were 1.3 and 0.3 transdiameters in lengtli respectively. 



The cytoplasm is coarsely granular, with numerous, minute, blue-green oil droplets scattered 

 through its peripheral zone. Several yellowish citrine-colored bodies were present, probably food 

 masses. The general color of the organism is aniline yellow shading to buckthorn brown, diffused 

 throughout the cytoplasm. Jlinute, dark refractive granules are also abundant. No striae or 

 other surface markings could be detected. A thin-walled, hyaline cyst, somewhat larger than 

 the body, enclosed it. 



