494 MEMOIRS OP THE UNIVERSITY OF CALIFORNIA 



Erythropsis extrudens sp. nov. 



Plate 12, figure 130; text figures SS, 11; TT 



Diagnosis. — A large species with rotiind body, flattened anteriorly, slightly 

 laterally compressed posteriorly; epicone at left forming 0.2 total length; 

 hypocone deeply furrowed ventrally by tentacular recess ; girdle disjDlaced pos- 

 teriorly about 0.5 total length; stout oblique contractile prod or tentacle with 

 capitate-pointed end, terminating in a stylet ; ocellus slightly protuberant with 

 concentric hemispheroidal lens, black pigment, and red core. Length, 89/^. 

 Pacific, off La Jolla, California, July. 



Description. — Tlie body is rotund, collapsed posteriorly in individuals which have dropped 

 off their tentacle, spheroidal in active forms with tentacle intact. The anterior end is much 

 flattened and the posterior notched bj' the deep sulcus and tentacular recess. In collapsed 

 individuals the posterior end is laterally compressed to about 0.5 transdiameter anteriorly. 



The body is so diversified by the girdle and its attendant paracingiilar grooves, the pro- 

 truding eyespot, the deep sulcus, and the basal mass of the tentacle that the unraveling of its 

 complicated structure is a matter of serious difficulty, especially since the animal while intact 

 is incessantly on the jump, so that complete camera outlines are impossible and the views 

 presented change with every move of the animal. The analysis here given is the result of the 

 prolonged study of three different individuals, only the first of which possessed this tentacle, 

 the mutilated base alone remaining on the other two. 



The greatest difficulty attends the analysis of the girdle and sulcus, because of their routes on 

 the flattened apex and across the black pigment mass, and because of the paracingular grooves 

 which confuse the observer. The analysis made on the three individuals is sufficiently coherent 

 to lend support to the hope that it is the correct one, but the difficulties are so baffling that 

 certainty has not been attained. 



The girdle is of the (ryrodinium type, that is, displaced at its distal end posteriorly for a 

 considerable distance, about 0.5 of the total length of the body. The flagellar pore of the 

 transverse flagellum lies in a depression just anterior to the ocellus. B'rom this point the girdle 

 sweeps dorsally around the flattened epicone under a widely ovei'hauging upper lip and descends 

 rapidly as a relatively shallow furrow, obliquely posteriorly across the right face, terminating 

 at a posteriorly directed notch on the edge of the deeply infolded, ventral sulcus. The very 

 active transverse flagellum traverses the proximal 0.6 of this girdle. 



The sulcus invades the epicone for a short distance above the anterior flagellar pore, skirts 

 the right side of the ocellus, sinks deep into the tentacular recess which is continued posteriorly 

 across the antapex. No longitudinal flagellum could be found. Its point of origin, or the 

 posterior flagellar pore, may be located at the opening of the posterior pusule. The notch at 

 the distal end of the girdle was not detected on the individual with tlie tentacle while it was 

 active. This is probably the attachment area. 



The epicone thus has a length on the left side of the sulcus of about 0.2 and on the right side 

 of about 0.66 of the total length of the body, but owing to the rapid descent of the girdle in its 

 distalmost part the epicone as a whole forms but a small part (less than 0.1) of the total body. 



The girdle is attended, in fact paralleled throughout most of its course, by certain surface 

 depressions, or paracingular grooves or lines (fig. RR, post, and pre. par. I.) strongly suggestive 

 at first sight of the slightly impressed, spirally twisted sulcus of Pauchetia and Cochlodinium. 

 Repeated efforts to bring these shallow markings into agreement with such an interpretation 

 and to give to the furrows the organization of Pouchetia which the presence of the eyespot leads 

 one to expect were fruitless. Semiapical views of collapsed and therefore quiet individuals 



