286 MEMOIES OF THE UNIVERSITY OF CALIFORNIA 



ill proportions, being more attenuate conical and lacking the distal eurvatiu-es 

 of apex and antapex and surface striae characteristic of G. spirale. It thus 

 a])pears to be as distinct from G. spirale as many other species of the genns. 

 It is closely related to ]N[eunier"s (1910) species found in Arctic waters, G. 

 fusiformc nom. sp. nov. (G. fnsus Meunier) (fig. EE, 8) and G. Jacliryma 

 (fig. EE. 6). The proportions, however, are different, i^articularly so in the 

 case of the latter species, with its broad, blunt posterior end and slender atten- 

 uate anterior end. The location of Schiitt 's species is entirely unknown and the 

 temperature relations of these species cannot be compared. 



Gyrodinium biconicum sp. nov. 



Plate 4, figure 46 ; text figure CC, 12 



Diagnosis. — This is a small species with slender fusiform Ijody. its length 

 3.57 transdiameters ; girdle a descending left spiral, displaced 0.57 transdiam- 

 eter ; sulcus extending from apex to antapex, with torsion of 0.5 transdiameter ; 

 color, pale glaucous blue. Length, 68,«. Pacific off La Jolla, California, July. 



DescrdptioX. — The body is slender fusiform, tapering sharply anteriorly, less so posteriorly, 

 its length 3.57 transdiameters at the widest part. The epicone exceeds the hypocone in length 

 by 0.1 S of its own length. It is slender conical, about 45°, with a slight sinistral flexure above 

 the anterior pore region. It has a length on the left and right sides of about 0.35 and 0.77 

 respectively of the total length of the body. The hypocone is slightly broader than the epicone, 

 its posterior end forming a cone of about 70°, rounding anteriorly. The entire body has a slightly 

 sigmoid curve in its general outline with the concavity on the right face. 



The proximal end of the girdle meets the sulcus at a distance from the apex of 0.35 of the 

 total length of the body. It follows a descending left spiral course around the body and its distal 

 end joins the sulcus at a distance from the apex of 0.77 of the total length of the body, being 

 displaced about 1.57 transdiameters, and with an overhang of about 0.25 transdiameter. The 

 furrow has a width of about 0.15 transdiameter, and is deeply impressed with smooth borders. 

 The sulcus is a narrow, shallow trough extending from the apex to near the antapex in a sigmoid 

 curve which gives it a torsion of about 0.5 transdiameter. It terminates near the left side of the 

 antapex. The anterior flagellar pore opens at the anterior junction of the sulcus and girdle and 

 the posterior pore slightly below the posterior junction. The transverse flagellum traverses 

 nearly the entire length of the girdle and the longitudinal flagellum has a length about equal to 

 that of the body. 



The nucleus is a spheroidal body located near the center of the organism. In the individual 

 figured it was elongate ellipsoidal, evidently a predivision stage. Its axis in the other specimens 

 was about 0.57 to 0.73 transdiameter in length. 



A large globular pusule opens into the anterior flagellar pore, a smaller sacklike one into the 

 posterior pore. The cytoplasm is very clear and transparent with few food bodies. In the apical 

 region of both indi\'iduals an irregular, light yellow, refractive body was located. In the 

 peripheral zone are numerous minute, blue-green oil droplets. The general color of the organism 

 is a diffused pale glaucous blue. No striations or other surface markings were present. 



DniEXSioxs. — Length, 52-68/'; transdiameter, 15-19/^; axes of nucleus, 13,« 

 and 11m. 



