PARASITES OF PROTOZOA 1063 



termes. Generally the parasite appears as a mass of spherical bodies, 

 each about one \\ or less in diameter and often with a stainable crescent 

 at one side, located in the central part of the nucleus. The spherical 

 bodies are a good deal smaller than are the nuclei in a plasmodium of 

 comparable size in the other parasite. The chromatin is usually re- 

 stricted to the periphery of the host nucleus; but, except for this re- 

 moval of the central part of the mass, it is little altered; and there 

 is no marked hypertrophy of the nucleus. In the nuclei of some hosts, 

 the proportion being greater on certain slides, rounded bodies with a 

 similar crescentic stainable area are located peripherally, the chromatin 

 mass being concentrated in the center. The distribution of these periph- 

 eral bodies is often such that a common embedding cytoplasm appears 

 unlikely. Further investigation is necessary to establish the nature of 

 this parasite. It may be a bacterial, coccoid parasite of the nucleus, com- 

 parable in certain ways, possibly, to Cavyococcus, described by Dangeard 

 (1902). 



In several instances multinucleate trichonymphas, with all nuclei 

 parasitized, have been found. These are the only multinucleate flagel- 

 lates of this genus that have ever been seen. Cytotomy generally ac- 

 companies division of the single nucleus, but binucleates occasionally 

 occur. 



Phycomycetes Other than Sphaerita and Nucleophaga 



Chytridiales of a number of genera other than Sphaerita and Nucleo- 

 phaga have been found parasitic on Protozoa, especially autotrophic 

 flagellates. Those described up to 1915, in the genera Olpidium, Pseu- 

 dolpidium, Rhhophidium, Phlyctochytrium, Khh'idiomyces, Saccomyces, 

 Rhizophlyctis, and Polyphagus, were discussed by Minden. They occur 

 in or on Euglena, Cryptomonas, Chloromonas, Chroococcus, Gleno- 

 dinium, Haematococcus, Chlamydomonas, Pandorina, and Volvox. Ol- 

 pidium arcellae is considered doubtful. 



Fungus parasites, which are probably Chytridiales, have been found 

 in cysts of a number of ciliates. Stein (1854) found many cysts of 

 Vorticella microstoma with up to three or four protuberances perforating 

 the wall and extending a short distance free. Each protuberance was 

 an extension of a rounded body {Mutterblase) within the cyst. From the 

 terminal opening a thin, gelatinous, clear fluid was reported to escape. 



