PARASITES OF PROTOZOA 1083 



CILIOPHORA 



Ei/ciliata. — There are few reports of ciliates parasitizing other Proto- 

 zoa, except for Phtorophrya and Hypocoiiia. Penard (1904) found a 

 cihate, which seemed to resemble Blepharisnia, in a large percentage 

 of the heiiozoan Raphidiophrys vhidis. The intracytoplasmic forms 

 showed different degrees of development and lived many days in isolated 

 Heliozoa. An immobile organism, with a large contractile vacuole but 

 no cilia or flagella, was found parasitic in three-fourths of a large number 

 of Pseudodifjiugia horrida by Penard ( 1905a) . This, he stated, suggested 

 the larger ciliate in the heiiozoan, but its affinities are uncertain. Hertwig 

 (1876) reported that a hypotrich bored into the body of Podophrya 

 gemmipara, in the region in which the body is joined by the stalk, and 

 destroyed the acinetid. 



A number of apostomatous ciliates are parasitic in other Foettin- 

 geriidae. The most completely known of these is Phtorophrya insidiosa 

 Chatton, A. Lwoff and M. Lwoff, 1930, which is parasitic on Gymno- 

 dinioides corophn. The phoront of Phtorophrya is attached to the phoront 

 of Gymnod'niioides, which occurs on Corophiuni acutuni. The body of 

 the parasite leaves the phoretic cyst and introduces itself into the body of 

 its host, becoming a parasitic trophont. It grows rapidly, ingesting the 

 cytoplasm of its host, and soon comes to occupy entirely the otherwise 

 empty cyst of Gymnodinioides. By division, four to eight small ciliates, 

 the tomites, are produced. These escape from the host cyst and swim 

 actively in search of another phoront of Gymnodinioides. 



Chatton and Lwoff (1930, 1935) described also the following in- 

 completely known species of this genus of ciliate parasites: Phtorophrya 

 mendax in the phoronts of Gymnodinioides inkystans; P. fallax in this 

 same host species; P. steueri in Vampyrophrya (?) stetieri; P. hathypela- 

 gica in Vampyrophrya bathypelagica. 



The Hypocomidae, like most other Thigmotricha, occur on bivalves 

 or snails, except for species of the genus Hypocoma, which are parasitic 

 on other Protozoa. Hypocoma parasitica (Fig. 199G-I) was found by 

 Gruber (1884) and Plate (1888) on marine vorticellids, especially 

 Zoothamnium, on the coast of Italy. Plate recognized a second species, 

 H. {"Acinetoides") zoothamni. The ciliates occur firmly fixed to the 

 host, and suck out the contents of the zooids. Hypocoma acinetarum 

 Collin is ectoparasitic on Suctoria. Collin (1907) found it on various 



