1064 PARASITES OF PROTOZOA 



forming a globule enclosing about thirty "young," resembling cer- 

 tain Monds forms, and, when dispersed, having movements like them. 

 Similar structures were shown in a cyst of Vorticella nebulijera. At that 

 time Stein considered this to be a mode of reproduction of Vorticella. 

 Cienkowsky (1855b) recorded similar bodies in cysts of Nassula am- 

 bigua C^N. viridis"), describing the appearance of clear vacuoles in the 

 cyst contents and the development of "spores," from many of which a 

 short process broke through the wall of the cyst and permitted the es- 

 cape of the swarm spores. Lachmann (1856) mentioned these observa- 

 tions as showing another kind of reproduction in ciliates. Cohn (1857), 

 however, remarked on the resemblance of these "microgonidia," with 

 their flask-formed "mother cells," to the chytrids of many plants. In their 

 text Claparede and Lachmann (1860-61) discussed the phenomena as 

 forms of reproduction by embryos, adding observations of their own on 

 similar structures in Urnula epistylidis; but in their footnotes they stated 

 that these were Chytridium. Stein (1859) regarded them as parasites, 

 comparing them with Saprolegniales and in particular with Pythium 

 entophytum Pringsheim; but their characteristics are suggestive of Olpid- 

 ium. Stein recorded similar bodies from cysts of Stylonychia pustulata, 

 Holosticha (Oxytricha) mystacea, dead Tokophrya (Acineta) lemnarum, 

 and Ale t acineta (Acineta) mystacina (observations of 1854). On the 

 motile bodies escaping from a Vorticella cyst he saw a single flagellum. 



Species of Olpidium, which differ from Sphaerita in the elongation 

 of the exit tube, occur in certain rhizopods and in Suctoria, as well as 

 in Euglena. O. amoebae was described by Mattes (1924) from Amoeba 

 sphaeronucleolus; it is said to parasitize a rotifer also. G5nnert (1935) 

 named O. acinetarum a chytrid which destroyed a culture of Lernaeo- 

 phrya capitata and Podophrya maupasii within a few days. The spores 

 are relatively large, from 2.5 to 3 \\ in diameter, equaling the larger 

 ones of Sphaerita; and Mattes found a relatively long posterior flagellum. 



Khizophidium and Polyphagus belong to the Rhizidiaceae, in which 

 there is a restricted mycelium. Khizophidium beauchampi has recently 

 been described by Hovasse (1936) in Eudorina illinoisensis. A heavy 

 infection, exceeding 90 percent, occurred homogeneously in these phyto- 

 monads in a large lake. The zoospore, which has a single long flagellum, 

 becomes fixed to the coenobial surface and germinates by the emission 

 of a tube which penetrates a cell and functions as a sucker. The part 



