KOFOID AND SWEZY: UNAEMORED DINOFLAGELLATA 503 



It might appear tliat this was a contracted individual of some other species 

 with the ocelhis in disintegration. However, the fact that in our experience this 

 organ persists longer than any other structure after cytolysis, and the lack of 

 any evidence that it disintegrates in situ prior to cytolysis, lead us to conclude 

 that the lohed structure of the elements of the ocellus is not a mere artifact. 



Erythropsis minor sp. nov. 



Plate 12, figure 131 ; text figure SS, 9 



Diagnosis. — A small species Avith stout, pyriform, ventrally arched body; 

 tapering hyi:)OCone ; girdle displaced 0.45 transdiameter ; ocellus 0.5 trausdiam- 

 eter in length with red core; lens and ])lack melanosome each simple, hemi- 

 sjDerical ; prod short, tapering, with very short stylet. Length, 48m. Pacific oif 

 La Jolla. California, July, August. 



Description. — Body stout pyriform. asjanmetrieal, its leugth (excluding tentacle) 1.4 trans- 

 diameters at the widest part which is at the anterior end of the hypocone. Ventral surface 

 concave, dorsal convex. Doi-soventral diameter 0.88 transdiameter. Epicone relatively large, 

 its length, at right of sulcus, 0.5 transdiameter. There was no apical horn. Owing to the large 

 size and protuberance of the ocellus the epicone on the left ventral region is scarcely exposed 

 at all in ventral view and, as a whole, is pushed to the right and has little dorsal surface. The 

 hypocone is widest a short distance below the girdle and contracts distally in an angle of about 

 30° to a rounded asynnnetrical antapex. The right side is the longer, but the appearance of 

 asymmetry is increased by the obliciuity of the point of view in the drawing. It was less evident 

 in other views' and disappeared entirely as the animal rounded up prior to cytolysis. 



The girdle is peculiar in not completely encircling the body and in having its proximal end 

 almost at the anterior end at the left shoulder fully 0.25 transdiameter in the horizontal direction 

 from its distal end. It descends rapidly in a left spiral so that the intercingular displacement 

 is aliout 0.5 transdiameter in the vertical direction. The furrow lias a fairly uniform width 

 tliroughout of 0.09 transdiameter. Its lower margin extends considerably beyond the upper, 

 and its trough is rather deeply indented. The transverse flagellum extends almost to the end 

 of the girdle and arises from the anterior flagellum pore immediately in front of the lens. No 

 paracingular grooves or bands were noted. 



The sulcus begins near the center of the epicone. runs to the left to its junction with the 

 girdle. It turns .sharply to the right, following closely the contour of the ocellus, and joins the 

 distal end of the girdle at the level of the lower edge of the melanosome, and extends directly 

 posterior to the antapex. Its vertical displacement is 0.45 transdiameter, but the length of the 

 oblique intercingular region is more than 0.5 transdiameter. It is a narrow channel throughout, 

 but opens internall.v in the antapical region into the tentacular recess. This is very short, 0.27 

 transdiameter in length, and is broadly campanulate in form, its distal opening being 0.4 

 transdiameter across. 



The prod is a slender regular conical structure of lO" with a roundetl tip and minute terminal 

 stylet asymmetrically located. It is not quite axial in j)Osition and inclines ventrally about 10° 

 from the major axis. Its length when (fully?) extended wa.s 0.75 and when contracted 0.4 

 transdiameter. No trace of longitudinal or circular fibers or of surface granulations was noted. 

 A distinct longitudinal flagellum was found in this species. It persisted for some time, was 

 noted in various positions of the body, and was active in propulsion of the body. It takes its 

 origin from the posterior flagellar pore located on the dorsal wall on the right side of the 

 tentacular recess behind and to the right of the prod a short distance within the recess. It was 

 about twice as long as the prod. 



