KOPOID AND SWEZY: UNARMORED DINOFLAGELLATA 499 



evidently a transition form close to it. The ventral position of the prod is more 

 marked than in any other species, and its differentiation into shaft, head, and 

 stylet most complete, while the spiral tract on its surface Avas not detected in 

 any other species. 



Erythropsis hispida sp. nov. 



Plate 12, figure 127 ; text figure SS, 2 



Diagnosis. — Mediiun sized species with ovoidal body, its length 1.46 trans- 

 diameter; girdle displaced 0.6 trausdiameter; ocellus not protuberant, lens com- 

 posed of a row of six spheroids at the left of the sulcus, pigment mass spheroidal, 

 dark brown with lu'ownish radiations; prod slender, not capitate, hispid, with 

 short terminal stylet; peripheral vacuoles elongated, crowded, orange j3ink. 

 Length, 89^*. Pacific off La Jolla, California, August. 



Description. — The body is ovoidal, its length 1.4G transdiameters, measured at the widest 

 part, which is slightly above the equator. The dorsoventral diaiueter slightly exceeds the trans- 

 verse. The epicene is much smaller than the hypocone and is shifted towards the right by the 

 displacement of the girdle, which is about 0.6 trausdiameter. The height of the epicone at the 

 proximal ejid of the girdle is 0.12 of the total length of the body and 0.5 at its distal end. The 

 apical region is highest at the left, slopes rapidly to the right and is less flattened than usual. 

 No anterior horn was noted. The hypocone forms more than 0.7.5 of the body, is distended in 

 an equatorial region on the sinistral face and is slightly flattened at the antapex, especially in 

 lateral view. 



The girdle forms a steep, descending left spiral, disjdaced distally 0.6 trausdiameter. It is 

 steepest in its distal region on the ventral face. Its two ends reach the median plane. The 

 transverse furrow is very narrow, 0.04 trausdiameter in width, and deeply impressed. Tlie 

 precingular groove runs subparallel to the girdle throughout its course, diverging anteriorly 

 from it as it proceeds distally, from one width of the furrow at the proximal end to four widths 

 at the distal end. The distal end of the groove turns abruptly anteriorly and appears to die 

 out alongside the svilcus. The surface between this groove and the transverse furrow is broadly 

 concave. No postcingular groove was noted. The sulcus begins at the summit of the epicone 

 to the left of the main axis, curves to the right, joins the girdle, curves in a slight convexity to 

 the right of the ocellus, joins the distal end of the girdle and merges in the deep, terminal, axial, 

 tentacular i-ecess. This cavity is 0.27 of the total length of the body in length and about 0.2 

 of the greatest diameter in width when it expands about the base of the tentacle. It contracts 

 slightly midway of its length and flares distally into the posterior opening aboi\t 0.25 trans- 

 diameter acro.ss. The left flap of the sulcus folds slightly over the right, hiding the upper part 

 of this tentacular recess. 



The transverse flagellum does not completely encircle the body. No longitudinal flagellum 

 was noted and an attachment area on the anterior lip of the distal end of tlie girdle was not 

 detected. 



The prod was not observed in full activity. As noted in the single individual of this species 

 which we have seen it was a slender, almost cylindi'ical structure, located in the axis and directed 

 posteriorly. Its total length, including the short stylet, was almost equal to the ti'ansdiameter 

 and its diameter about 0.08 of the same. It has a globular enlargement at its base whose 

 diameter is 1.5 that of the shaft. It enlarges .slightly towards its distal end, but is only slightly 

 cai)itate even when contracted. At the distal end it bears a short, acute stylet whose length 

 does not exceed the diametci' of tlie |irod. Its axis (foiitains a .slender axial thi'ead, the retractor 



