KOFOID AND SWEZY: UNARMORED UINOPLAGELLATA 473 



also encysted and had external thickenings of the cyst wall about the apex above the apical loop 

 of the sulcus and along the girdle, indicating greater secretory activity anteriorly and along the 

 motor region. 



■ Dimensions. — Length, 68-80/* ; transdiameter, 50-67/* ; major and minor axes 

 of nucleus, 37^2/* and 20-25/*; ocellus, major axis, 21-26/*. 



Occurrence. — The first specmien was taken from a liaul made on July 27, 

 1917, 4 miles off La Jolla, California, with a No. 25 silk net from a depth of 

 80 meters to the surface, in a surface temperature of 21-9 C. Another from 

 a haul Aug-ust 17, 0.75 mile off La Jolla, at a depth of 80 meters to the surface, 

 in a surface temperature of about 22° C. 



Activities. — One individual was ke})t under observation from 2 p.m. to 3 

 P.M., when eytolysis ensued. It was encysted and inactive, but when the slide 

 was tapped it rotated a few turns within the cyst. When rolled over by moving 

 the cover glass it always returned to the same position as though passively by 

 gravity. 



Unimpeachable evidence of the holozoic nutrition of this species is presented 

 by the remains of the component plates of the theca of a large Pendinitiiii 

 within a food vacuole of an encysted individual of this species. Its contents 

 had been almost completely digested. The manner in which a Pouchetia, with 

 an almost labile protoplasmic body, devoid of protrusible food-grasping organs, 

 can capture, hold, and engulf a Peridiniam, more than half its size, j^asses com- 

 prehension. From the location of the Peridinium in the body of its captor it 

 seems probable that it was taken in through the sulcus below the anterior 

 flagellar pore and the posterior end of the body, that is, mainly through the 

 intercingular siilcus. A moliility of this region sufficient to capture a mobile 

 Peridinium and ingest its rotund body with protruding apical and antapical 

 regions requires an efficiency of function quite beyond that suggested by the 

 structure of these regions of Pouchetia, and exceeds, to a high degree, our jjre- 

 conceptions as to the instincts, reactions, and capacities of these unicellular 

 organisms. 



Comparisons. — This is one of the least specialized species of the subgenus 

 PonehefieUa with concentrated ocellus. Its lens, when in juxtaposition with a 

 food mass, is slightly lobed, its melanosome is irregular if not slightly lobed, 

 and detached glo])ules of red or black pigment are found near the girdle. Tlie 

 integration of lens and pigment is well established, but the position of the ocellus 

 is shifted by the pressure of food masses. 



Pouchetia voracis is close to P. striata, but is less rotund, more asymmetrical 

 posteriorly, has a shorter apical sulcus, and proximal epicone with less torsion, 

 and less intercingular dis]ilaccment of the girdle. The ocellus has a slightly 

 more anterior position and similar structure, but is less distinctly laminate. 

 It also lacks entirely the longitudinal striations characteristic of P. striata. 



