KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 457 



Pouchetia purpurata sp. nov. 



Plate 8, figure 87 ; text figure PP, 3 



Diagnosis. — Medium sized species Avith ol)OA-oidal body, widest anteriorly, 

 length 1.75 transdiameters ; girdle a descending left spiral of 1.4 turns, dis- 

 placed 0.48 of the total length : sulcus with apical extension and antapical loop ; 

 torsion 1.2 turns; ocellus distributed, postmedian; lens elongated, segmented; 

 melanosome amoeboid, with granular processes ; plasma dahlia purple. Length, 

 88f*. Pacific off La Jolla, California, July. 



Description. — The body is obovoidal, wider anteriorly, flattened ventrally, more convex 

 dorsally, its length 1.75 transdiameters measured at the widest part which is about the level of 

 the anterior flagellar pore. The epicone exceeds the hypoeone in height by about 0.13 of its 

 own length and is wider and more rotund. Its length at the proximal and distal ends of the 

 girdle is 0.3 and 0.8 respectively of the total length of the body. Its ventral face is somewhat 

 flattened, the dorsal more convex. The apex is subhemispherical. The hypoeone is more con- 

 tracted, its length at the anterior and posterior ends of the intercingular sulcus being 0.7 and 

 0.2 respectively of the total length. The antapex is rounded and somewhat projected ventrally 

 by the arching of the dorsal side. 



The girdle leaves the sulcus 0.3 of the total length below the apex, makes 0.5 turn of a 

 descending left spiral with almost no posterior deflection, steepens rapidly 0.75 turn to 45° 

 and slackens up almost to the horizontal at its distal end of nearly 0.5 turn. It makes a total 

 of 1.4 turns with a total displacement of 0.48 total length, or 0.85 transdiameter. The furrow 

 has a width of 0.08 transdiameter, is not deeply impressed and has a somewhat overhanging 

 anterior lip. Tlie sulcus was not fully determined on tlie epicone. It appears to start near the 

 apex, curves but slightly in place of the usual apical loop, but runs from apex nearly to the 

 antapex in a fairly uniform descending left spiral with a total torsion of 1.2 turns, 0.6 of which 

 is in an abruptly steepened antapical loop. It is a narrow channel about 0.5 the width of the 

 furrow in the intercingular region, but widens out below in the antapical loop. The flagellar 

 pores are at the junctions of girdle and sulcus and the transverse flagellum runs the whole 

 length of the transverse furrow. 



The ocellus is of the diffuse type, postmedian, at the left and close to the distal end of the 

 intercingular sulcus. Its length is unusually great, attaining 0.28 total length of the body, or 

 nearly 0.7 transdiameter. Its greatest diameter is 0.35 of its own length. It lies parallel to 

 the sulcus with the lens directed anterodextrally at an angle of about 35° from the vertical. 

 The lens is hyaline, glaucous green in color with a darker purplish plasma sheath surrounding 

 it and separating its segments. It is a slender shaft of four unequal segments enclosed within 

 a less distinctly differentiated outer sheath. This sheath is incomplete on its sinistral face. The 

 melanosome is more than 0.35 wider than the lens, its main mass forming a stout pitcher-shaped 

 body into which the end of the lens is thrust. From its anterosinistral margin a lobe projects 

 anteriorly and breaks up into an anastomosing, branching network of granular strands of 

 pigment. A disconnected strand of similar granules lies along the anterior lip of the furrow, 

 and several others in the peripheral plasma of the hypoeone adjacent to the distal end of the 

 girdle and sulcus. 



The nucleus is relatively snmll. It is an elongated, asymmetrical ellipsoid, located far 

 anterior in the center of tlie epicone. Its axes are 0.6 and 0.33 transdiameter in length respec- 

 tively and it is crowded with spirally wound, beaded chromatin threads. A pale ochraceous 

 food ball lies in the center of the very transparent plasma. A cluster of slender, greenish 

 diverging radial rodlets are located in the extreme posterior end, probably metabolic in origin. 

 In the peripheral plasma close to the pellicle are minute, uniformly distributed, greenish droplets. 



