236 MEMOIRS OP THE UNIVERSITY OF CALIFORNIA 



body. The sulcus extends anteriorly on the epicone for 0.S5 of its length, and posteriorly on 

 the hvpoeone for little more than 0.33 of its length, fading out at the pore of the longitudinal 

 flagellum at its posterior end. It is linear, lies in the median plane, and forms a narrow, uniform 

 channel about half the width of the transverse furrow, flaring slightly only in the anterior part. 



The surface is characteristically marked with very fine, delicate, close-set longitudinal striae 

 of uniform intervals on both epicone and hypocone. These anastomose or die out distally so 

 that the uniformity of interval is maintained throughout the whole surface. At the girdle there 

 are about fifty of these striae on one face of the botly. Beneath the pellicle there is a thin layer 

 of faintly developed slender rodlets about 0.06 transdiameter in length. These stand perpen- 

 dicularly to the surface except in the antapex. where they are somewhat larger and are crowded 

 into the narrowing apex. Scattered spheroidal refractive granules lie just beneath this layer of 

 rodlets. 



The bodj' as a whole is quite translucent and of a greyish color tinged faintly with greenish 

 yellow. It is crowded with numerous spherical pinkish vacuoles 0.06 to 0.12 transdiameter in 

 diameter. The broadly ellipsoidal nucleus lies just beneath the girdle with its long axis inclined 

 to the right anteriorly. It is about 0.5 transdiameter in length in its greatest axis, and is filled 

 with a coarse, moniliform chromatin thread. No chromatophores and no pusules could be 

 detected. A few small refractive granules were clustered near the nucleus. Probably holozoic. 



Dimensions. — Length, 108."; transdiameter. 50/^; greatest diameter of 

 nucleus, 26/^. 



OccrRREXCE. — This was taken July 5, 1917, with a No. 12 silk net, in a haul 

 6 miles off La Jolla, California, from 80 meters to the surface and in a surface 

 temj^erature of 21°1 C. On July 11 it was taken with a No. 25 silk net. 1 miles 

 off La Jolla. in a haul from 80 meters to the surface, and on July 27 and on 

 August' 21 at the same place and under approximately the same conditions. 



Co:mi\\risoxs. — The structure of the girdle places this species in the genus 

 Gymnodinium, but the striate surface and rodlets recall those of many species 

 of Gyrodinium, such as G. acntnm. It belongs to the subgenus Lineadinium, 

 but has no near relatives in form, proportions, or size. It is the most finely 

 striated species in the genus and appears to be a imicpie and isolated tyjie. 



Gymnodinium multistriatum sp. nov. 



Plate 4, figure 37 ; text figure Y, 1 



Diagnosis. — A medium sized species with biconical body, its length 1.47 

 transdiameters ; girdle submedian, displaced 0.25 transdiameter; sulcus ex- 

 tending from apex to antapex ; surface finely striate ; color grey green and yellow 

 ochre. Length, 100^*. Pacific off La Jolla, California, August. 



Description. — The body is rotund biconical, asjTnraetrical, almost rhomboidal in shape, nearly 

 circular in cross-section, with rounded apices, its length 1.47 transdiameters at the widest part, 

 which is equatorial. The epicone is slightly larger than the hypocone in size, its length being 

 greater by 0.1. It has the form of a cone of about 65°, with a blunt apex and broad base, its 

 right side about 0.23 longer than its left side. The right side is slightly more convex than the 

 left. It has a length on the left and right sides of 0.43 and 0.59 respectively of the total length 

 of the body. The hypocone forms a cone of about 70° with its left side longer than the right 

 and a blunt antapex excavated on the ventral side by the suleal notch. Both sides are only very 

 slightly convex. 



