1074 PARASITES OF PROTOZOA 



and a rod-formed structure called by Georgevitch a blepharoplast. 

 Growth, nuclear division, and plasmotomy result in rosettes, usually of 

 eight individuals and a residual body. Longitudinal division also occurs. 

 Flagellated stages were rarely found. The evidence that the parasite 

 is Leishtnania is unconvincing, and is certainly inadequate as a basis 

 for extending the distribution of that genus to such an unusual location. 



SARCODINA 



The genus Pseudospora, which comprises parasites of true algae and 

 of Volvocidae, has been placed in the Proteomyxa; but there appears 

 to be good reason for accepting the suggestion of Roskin (1927) that 

 it belongs rather in the Bistadiidae of the Amoebida. P. volvocis, first 

 described by Cienkowski (1865), was later reported from Volvox by 

 Robertson (1905) and Roskin (1927). It seems possible that the 

 amoebae found by Molisch (1903) and Zacharias (1909) in Volvox 

 minor {V. aureus) belonged to this genus, though the authors do not 

 refer to earlier observations on parasites of Volvox, and their work is not 

 cited in later accounts of Pseudospora. Roskin (1927) described P. 

 eudorini from Eudorma, in which flagellate Robertson (1905) had re- 

 ported P. volvocis. 



In its free-living state both these species are small, helio2oa-shaped 

 forms, with immobile or slow-moving pseudopodia. The heliozoan form 

 becomes amoeboid, with lobose pseudopodia, on contact with the host, 

 which it enters. Within the coenobium, the amoeboid form engulfs 

 the cells and undergoes repeated division. After a period, the parasite 

 comes to the surface of the colony, and there is rapid transition to a form 

 with two relatively long flagella. The organism may lose the flagella 

 and become amoeboid, may form cysts and the free heliozoan form, and 

 the heliozoan type may transform into a flagellate, as well as into an 

 amoeboid form. 



It is generally considered that confusion with parasites is the basis 

 of the accounts of complicated life cycles in Arcella. The earlier ob- 

 servations on this testacean were discussed by Dangeard (1910), who 

 offered convincing evidence that the small amoeboid bodies, supposed 

 to be produced in numbers by repeated exogenous or simultaneous en- 

 dogenous budding (Awerinzew, 1906; Elpatiewsky, 1907; Swarczewsky, 

 1908), and variously interpreted by authors as reproductive phases of 



