PARASITES OF PROTOZOA 1041 



the enlargement of the nucleus to between three and four times its 

 normal diameter, indicates the presence of Nucleophaga. Greeff (1866) 

 mistook the early plasmodial stages of Nucleophaga for young amoebae 

 entering the nucleus of A. terrkola. 



Stein, who had mistaken parasitic bacteria for reproductive elements 

 of ciliates (p. 1034), observed Sphaerita-Wke. Chytridiales in a number 

 of flagellates (1878, 1883). His plates include figures of what are 

 probably such fungi in Monas gut tula, Chlamydomonas alboviridis, 

 Euglena viridh, Trachelomonas volvocina, T. hispida, Phacus pleuronec- 

 tes, Tropidocyphus octocostatus, Anisonema grande [A. acinus), Gleno- 

 din'tum pulvisculus, Heterocapsa triquetra, and Dmopyxis laevis. In 

 many of these he represented the escape of minute, flagellated organisms. 

 He likewise concluded that these are reproductive elements, the nucleus 

 undergoing growth and fragmentation, and giving rise thus to endoge- 

 nous germs reproducing the flagellate. This theory of flagellate reproduc- 

 tion was accepted by Kent (1880-82), who confirmed the observations 

 of Stein on Euglena and other euglenid flagellates. Ryder (1893) com- 

 pared an "endoblast" figured in E. viridis, from which flagellate "germs" 

 were said to escape and become amoeboid forms developing into adult 

 euglenas, with Stein's reproductive stage. Discussion of the early errors 

 of interpretation is given in many of the publications on chytrid para- 

 sites of Protozoa, particularly those of Dangeard (1886b, 1895), Penard 

 (1905b), Chatton and Brodsky (1909), and Mattes (1924). 



The evidence for Stein's notion of reproduction did not satisfy Klebs 

 (1883), who pointed out that the "Keimkugel" was a sporangium of 

 "Chytridium spec," which, he stated, is one of the most frequent para- 

 sites of Euglena. The problem was studied independently by Dangeard, 

 and he arrived at the same conclusion (1886a, 1886b) . The name Sphae- 

 rita endogena was given ( 1886a) to cytoplasmic chytrids in the rhizopods 

 Nuclearia simplex and a species of Heterophrys, which was later (1886b) 

 named H. dispersa. The illustrated account of the parasite (1886b) in- 

 cluded a report of its occurrence in Euglena viridis. Dangeard (1889a), 

 recorded S. endogena in Phacus pyrum, Trachelomonas volvocina, and 

 T. hispida; later (1889b) he described it in Euglena sanguinea and P. 

 alata; and in 1895 he gave a fairly complete and well-illustrated descrip- 

 tion of the life history of the parasite in Euglena [viridis?). Serbinow 

 (1907) studied the chytrid in E. viridis and E. sanguinea. 



