262 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



trailing longitudinal one and tlie ril)bou-like transverse one, and travel in the 

 normal rotating fashion. There is apparently a sulcus and a postmarginal 

 suleal notch. No determination of the dinoflagellatc nature of the nucleus vras 

 made. The organism was colorless, about 18a* in length and of nearly the same 

 width . 



Somewhat similar "spores" with girdle and suleal notch were previously 

 described by Lackmann (1906) as macrospores of Tiuthuiopsis campanula and 

 Cytliarocytis helix. Lohinann (1908) justly criticizes this interpretation and, 

 correctly in our oiDinion, regards it as wholly improbable that a cilitate proto- 

 zoan Avould have a dinoflagellate macrosi:)ore. The spores figured liy Lackmann 

 (1906, pi. 1, figs. 17-21) have a different appearance from those of Lohmann. 

 The_y are larger and taper more anteriorly. 



It may well be that Brandt's (1905) rej^ort that the swarm spores of the 

 Radiolaria are of the dinoflagellate type is based upon observations of parasitic 

 dinoflagellates and not radiolarian swarm spores. More evidence is essential 

 before this subject can be set forth in its correct relations. In the meantime 

 we leave Lolmiann's species tentatively in Gymnodinium. It will, in all proba- 

 bility, find its place ultimately among the Blastodiniidae or other parasitic 

 representatives of the dinoflagellates. 



Gymnodinium translucens sp. nov. 



Plate 2, figure 17; text figure Y, 2 



Diagnosis. — A medium sized species with ellipsoidal body, its length 1.93 

 transdiameters ; girdle sulmiedian, displaced about twice its own width; sulcus 

 extending from apex to antapex ; surface sparsely striate ; color, bluish glaucous, 

 very hyaline. Length, 87f. Pacific off La Jolla, California, June. 



Description. — The body is slender ellipsoidal, pointed anteriorly, truncate posteriorly, its 

 length 1.93 transdiameters at the widest part. A cross-section of the body is nearly circular 

 with the midventral surface slightly indented. The epicone exceeds the hypocone in size, its 

 length being greater by 0:14. Its transdiameter is also slightly larger. It is dome-.shaped with 

 high rounded sides and a short, sharply pointed apex. It has a length on the left and right sides 

 of 0.51 and 0.60 respectively of the total length of the body. The sides of the hypocone are less 

 convex than those of the epicone. Posteriorly it is deeply emarginate by the suleal notch, with 

 the two lobes broad and rounded. 



The girdle is submedian in position. Its proximal end joins the sulcus at a distance from 

 the apex of 0.51 and its distal end 0.60 of the total length of the body. The furrow is wide, 

 about 0.09 transdiameter, and deeply impressed, with the sides gradually curving out to the 

 surface of the body. The borders are marked by a double-contoured line, slightly crinkled and 

 blue green in color. The sulcus extends from the apex to the antapex in a slightly sinuous line. 

 It is very narrow and rather shallow on the epicone, expanding about three times this width 

 beyond the anterior flagellar pore. After passing the distal end of the girdle it becomes much 

 wider and sinks deeper into the body until, near the antapex, it reaches the dorsal surface, 

 bifurcating the posterior part of the body. The two lobes are broad and rounded. The anterior 

 flagellar pore opens at the proximal end of the girdle, near the place of union with the sulcus. 

 The posterior pore is slightly beyond the distal junction of girdle and sulcus. 



