456 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



horizontal for the rest of its course. It meets the sulcus at a point 0.16 of the length of the 

 body from the autapex. It forms a broad trough in a shallow constriction with the borders 

 slightly overhanging. The anterior flagellar pore is located at the anterior junction of the 

 girdle and sulcus and the posterior pore is found at the postmargin beyond the posterior junction 

 of girdle and sulcus about the width of a girdle. The transverse flagellum traverses about 0.2 

 of the length of the girdle. 



The sulcus invades the hypocone in a broad apical loop of 0.5 turn, terminating near the 

 apex. It forms a broad channel, only slightly narrower than the girdle, the lips on the epicone 

 forming a high ridge on its left and a lesser one on its right side. In its course below the anterior 

 flagellar pore it forms a deep trough which becomes shallower on reaching its distal junction witli 

 the girdle, and continues so in its path down the hyjiocone to its termination to the left of the 

 antapex. It forms an irregular descending left spiral with torsion of 0.75 turn. It is not 

 improbable that an antapieal loop completes a full turn dorsally. 



The ocellus is situated in the equatorial region, at the left of the intercingular sulcus. It is 

 of the diffuse type in its least integrated stage. It consists of a loosely aggregated group of 

 lenses and scattered melanosome. The lens is formed of six spherical, clear, bluish hyaline bodies 

 loosely massed together in an irregular linear series 0.33 transdiameter in length. The melano- 

 some is composed of more than a score of irregular, unequal spheroids of black pigment, varying 

 in size from 0.5-6/a in diameter and scattered in the peripheral plasma at the left and posterior 

 to the lenses, from the left of the anterior flagellar pore to near the antapex along the left margin 

 of the hypocone. The larger masses are found near the distal end of the lens. To the left of 

 the lens and closely associated with it is a long slender body, yellow ochre in color. It may be 

 the homologue of the pigmented core of the more integrated types of melanosome. Its axis is 

 directed anterosinistrally at 15° from the vertical. 



The nucleus is jiist postequatorial, ellipsoidal in shape with no visible chromatin strands in 

 the individual figured. Its major and minor axes are 0.40 and 0.26 transdiameters respectively 

 in length. 



A large, club-shaped pusule opens anteriorly into the anterior flagellar pore. A posterior 

 one was not noted. The cytoplasm is clear and finely granular. In the anterior portion of the 

 body and radiating from near the anterior flagellar pore is a gi'oup of slender, linear, green 

 rodlets or fluid-filled canals. In the midregion and sparingly elsewhere are small blue-green 

 oil droplets. A large primuline-yellow food mass was present near the ocellus. Thickly scat- 

 tered in the peripheral plasma are irregular, thin, uniformly distributed vacuoles filled with 

 blue-green fluid. No surface markings or striations were present. 



The general color is a pallid methyl blue mottled with the blue-green of the surface vacuoles. 

 The body was surrounded by a close fitting hyaline cyst which during observation became more 

 and more distended in the region of the sulcus, especially over the apical loop. 



Dimensions.- — Length, 73/* ; transdiameter, 54/* ; axes of nucleus, 26/* and 14/*. 



OcciTBEENCE. — One individual was taken July 25, 1917, 11 miles off La Jolla 

 with a No. 25 silk net in a haul from 80 meters to the surface in a surface 

 temperature of 27 ?1 C 



Comparisons. — This is the most primitive species of the subgenus Poiichetin 

 with diffuse ocellus. Its primitive features are shown in the slight intercingular 

 torsion and in the marked absence of integration in the ocellus as shown in the 

 degree of independence of the elements of the lens and the nntch divided and 

 widely scattered melanosome. The possibility of disintegration prior to cytoly- 

 sis is not excluded. As a rule, however, the ocellus resists these disintegrative 

 processes longer than the cytoplasm. 



