434 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



correlation between pigment formation and structural specialization within the 

 genus Poaclietin. 



Many if not all the species of this genus are holozoie in nutrition. The 

 evidence for this lies in the presence of food halls Avithiu food vacuoles in the 

 c}i:oplasm. the accumulations of the products of metabolism in the form of oil 

 globules, vacuoles, refractive rodlets and platysomes in the central or peripheral 

 plasma, and the presence of recognizable organisms within the food vacuoles 

 in a few cases. For example, P. voracis (fig. PP, 2) was found with the entire 

 theca of a species of Peri dint urn within it. 



It is possible that the small P. parva is holophytic, ])ut the only basis for 

 this conclusion is its ochraceous color. It is evident, however, that Lohmann's 

 figure is quite diagrannnatic and wholly inadequate to determine this matter. 

 There is no evidence tliat any of the other species have any chlorophyll or 

 xanthoi^hyll of their own. The yellow bodies found within them appear in all 

 cases to be in food balls. 



The interciugidar sulcus is probalily the mouth and it is not impossible that 

 the two piTSules may represent remnants of areas of ingestion. The capture 

 of organisms and their ingestion have not been observed. The ejection of 

 undigested remnants has been watched in P. ma.riHia. The antapex is rent 

 open, foi-ming a protoplasmic skirt, and the fecal mass is extruded (pi. 6, fig. 61) 

 from its opening. The resulting modifications, which are temporary, are one 

 cause of the varial)ility of the antapic-al region of this genus. It is also obvious 

 (fig. PP, 2) that the i)resence of large food masses may distort the contour or 

 even push aside ocellus and nucleus. 



The wide prevalence of the formation of cysts in Pouchctia is correlated 

 with this holozoie nutrition. Individuals within cysts frequently exhibit food 

 balls or meta])olic products (fig. P.) Such cysts are their digestion cysts 

 temporarily formed for a quiescent period of apjiropriation of a relatively 

 large volume of food. AYe have no evidence of binary fission within cysts in 

 Pouchefia. 



The cyst forms as a pellicle on the surface of the plasma and is ex|)auded 

 by the fluid accumulating within it by osmosis. The agency of the plasma, 

 especially along the sulcus, in this process is suggested by the more rajDid dis- 

 tension of the membrane immediately over this organ. 



DlSTEIBUTIOX 



Species of Pouchctia have been reported princii^ally from warm temperate 

 and tropical seas and only from more northerly waters receiving warm currents 

 from these warmer regions. It is unfortunate that Schiitt's monograph (1895) 

 gives no clue to the precise source of his species, P. com pacta, P. fusus, P. juno, 

 and P. schuctti nom. sp. nov. (=P. rosea (Pouchet) Schiitt). They are pre- 

 sumably from the Bay of Naples or from collections of the Plankton Expedition 

 in the Atlantic. Pouchet 's material of P. polyphemus and P. rosea came from 



