KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 445 



the protiiborant ocellus, flattening the spiral distally to 20° from the horizontal and turning 

 abruptly posteriorly at the posterior junction. The anterior flagellar pore is at the anterior 

 junction, and the posterior pore inunediately at the posteroir junction of girdle and sulcus. 



The ocellus is slightly postmedian in location, at the left of the anterior part of the iuter- 

 cingular sulcus. Its length is 0.5 transdiameter and the lens is directed horizontally to the left 

 side of the body, on whose margin about 0.5 of the body of the lens protrudes. The ocellus 

 consists of a spheroidal lens about the same size as the melanosome and 0.33 transdiameter 

 across. It is hyaline, finely laminate and has a narrow peripheral layer strongly differentiated. 

 In encysted and moribund animals it becomes more ovoidal in form, with the larger end pro- 

 truding and the melanosome sends out short stout processes. In the normal condition the black 

 melanosome is a hemispheroidal or rounded mass in which one face of the lens is lightly imbedded. 

 No bright colored central core was noted. Small detached strands of brownish-black melanin 

 lie parallel to the girdle in its margins. 



The nucleus is ellipsoidal, located anteriorly, and has about twenty beaded spiral chromatin 

 strands across one face. Its major and minor axes are 0.9 and 0.7 transdiameter in length 

 respectively. One or more long clavate pusules open anteriorly at the anterior flagellar pore 

 and what appears to be a long slender one passing anteriorly to the ocellus opens posteriorly 

 at the posterior pore. Irregular rounded double-contoured platysomes fill the peripheral plasma, 

 showing locally slight indications of linear arrangement. There are also the faintest of sug- 

 gestions of linear striae in the pellicle which persists on plasmolysis (Schiitt, 1895). 



The color of this organism is neither figured nor stated by Schiitt. Our own observations 

 are restricted to a single individual recorded at the time in our notes as having dark purplish 

 black granules along the girdle as cytolysis approached. 



l)i:\[Exsioxs. — Leugtli, 125/^; transdiameter, 70/s length of ocellus, 21/^; of 

 nucleus, 32^ and 22m. 



Occurrence. — One individual was taken July 3, 1906, 2.75 miles of La Jolla, 

 California, in a haul of a No. 20 net from 155 meters to the surface in a surface 

 temi)erature of 20°d C. 



Schiitt (1895) figures this species, presunial)ly from the Bay of Naples or 

 from the collections of the Plankton Expedition in the Atlantic. 



Comparisons. — Pouchetia juno is one of the most highly specialized species 

 of the subgenus Poucketiella with integrated ocellus. Its specialization is indi- 

 cated in the spherical, laminate lens, compact melanosome, median location, and 

 horizontal position of the ocellus; also by the extreme torsion of the sulcus of 

 2.5 turns, its extent from apex to antapex, and the prolonged apical loop. 



It is closely related to P. violescens, having the same t}TDe of ocellus, simi- 

 larly located, the same long apical loop, and about the same torsion of sulcus. 

 It differs, apparently, in coloration, proportions of body, and in the course of 

 the apica] loop, relative size of lens and melanosome, and striations. P. jiino 

 has not been reported to be violet in color, is more fusiform, does not have the 

 apical looj) crossing the apex, but encircling it only, has the lens much larger 

 than the pigment mass instead of equal to it, and has exceedingly faint stria- 

 tions instead of prominent ones. The possi1)ility of both falling within the 

 range of one varial)le species is not excluded. More material is needed to de- 

 termine this with certainty. 



