KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 381 



sulcus in their relation to tlie twisted posterior portion of the body. Both of 

 these forms we have found in the plankton at La Jolla and have no difficulty 

 in separating them. We therefore propose to separate his figure 77c as a new 

 species, C. scJuteffi. The elongate nucleus in Schiitt's figure is evidently that 

 of a predivision stage. 



CoMPARisoxs. — This species belongs with the subgenus Gluphodiuium and 

 lies midway between G. (joniudtum (fig. GG, 1) and C. vinctum (fig. HH, 3), 

 near the lieginning of the series showing an increasing curvature and distortion 

 of the body. The anteroposterior plane passing from apex to antapex is more 

 ventrad in position in C. schueffi than in C. (jeininatum and less so than in C. 

 vinctum, nearly equaling that of C. rosaccum (fig. HH, 4) in this respect. 



Cochlodinium scintillans sp. nov. 



Plate 10, figure 113 ; text figure GG, 11 



DiAGxosis.^ — A small species wdth subellipsoidal to biconical body, its length 

 1.4 transdiameters ; girdle a descending left spiral of 1.5 turns, displaced 0.74 

 transdiameter ; sulcus with apical loo]j and torsion of 0.5 turn; color, pearl grey 

 with reddish tones. Length, 38m. Pacific off La Jolla, California, July. 



Description. — The body is asymmetrically ellipsoidal approaching biconical, tapering at 

 both apices, circular in cross-section, its length 1.4 transdiameters at the widest part, which is 

 at the middle. The epicone is considerably larger than the hypocone, having a greater trans- 

 diameter as well as greater length. It has the shape of a cone of about 80° with the left side 

 slightly elevated, deflecting the blunt apex somewhat to the right. It lias a length on the left and 

 right sides of 0.26 and 0.84 respectively of the total length of the body. The hypocone is sub- 

 conical, its angle varying from 50° at the antapex to about 80° anteriorly, its sides slightly 

 concave. It is narrower than the epicone with a more slender pointed antapex. 



The girdle is a descending left spiral of 1.5 turns and a displacement of 0.74 transdiameter. 

 The distance from the apex of the proximal and distal ends is about 0.26 and 0.84 respectively 

 of the total length of the body. The furrow has a width of about 0.07 transdiameter, and is 

 deeply impressed with smoothly rounded borders. The sulcus forms a loop on the epicone, 

 terminating below the apex on the left side. After passing the anterior flagellar pore it is 

 deflected to the left with a torsion of 0.5 transdiameter in the intercingular part of its course, 

 beyond which it passes posteriorly to within a short distance of the antapex. Its width is about 

 one-third that of the girdle and the furrow is relatively deeply impressed. The anterior and 

 posterior pores are located at the anterior and posterior junctions of the girdle and sulcus 

 respectively. 



Tlie nucleus is reniform in shape and filled with fine, parallel, moniliform chromatin strands 

 following its longer axis. Its major and minor axes are about 0.51 anti 0.21) transdiameters in 

 length respectively. 



The cytoplasm is finely granular witli a number of greenish oil droj)lets scattered tlirough it. 

 In the posterior region was a large, sjiherical vacuole filled with a pink fluid. Below this was 

 a rounded body, orange rufous in color, and neai' the apex a smaller one of jasper red. The 

 general color of the cytoplasm is pearl grey with tints of red showing through it. This form, 

 like so many of the Gymnodinioidae, showed a striking play of color through the cytoplasm, 

 which is almost impossible of analysis anil still harder to reproduce adequately. 



