960 PROTOZOA AND OTHER ANIMALS 



list of hosts given by Chatton and Lwoff (1935, p. 371) includes cope- 

 pods, ostracods, amphipods, caprellids, the isopod Sphaeroma, and the 

 decapod Carcinus. When the crustacean is ingested by a sea anemone, 

 the phoronts excyst and become young trophonts. 



Apostomes of the genus Phtorophrya are hyperparasites on other 

 apostomes. The phoront is fixed on the phoront of the host species, and 

 the parasite introduces itself into the body of the other ciliate. It grows 

 rapidly and soon comes to occupy a cyst otherwise empty. Tomites are 

 eventually produced; these leave the empty cyst of the host and swim 

 actively in search of another host phoront. 



Rose (1933, 1934) reported two unnamed ciliates, considered by him 

 to be Foettingeriidae, parasitic in the oil drop in the oleocyst of the 

 siphonophore Galeolaria qjiadrivalvh. He thought it probable that the 

 cysts are attached to pelagic copepods. 



Apostomatous ciliates have been found in the digestive cavity of 

 certain ophiurans and the ctenophore Cestus veneris. Pericaryon cesticola 

 is unusual among Foettingeriidae in adhering firmly to the walls of the 

 gastrovascular cavity of its host. It has an apical stylet, which seems to 

 be an organelle of fixation. 



Sexual processes have been described in a number of Foettingeriidae. 

 Conjugation is contingent, as in other ciliates, and is of a common type 

 throughout the family. The trophonts conjugate and remain associated 

 during the formation of tomites. At the end of the series of fissions, 

 meiosis occurs, pronuclei migrate, and the tomites separate. 



While phoresy on Crustacea is known or presumed to occur in all the 

 Foettingeriidae, except in Phtorophrya, the host phoront of which occurs 

 on Crustacea, it is unknown in the Opalinopsidae. The vermiform, 

 elongated (up to 1,200 |j), vegetative forms of Chromidina elgans are 

 fixed to the renal cells of cephalopods by an apparently retractile apical 

 papilla. There is no mouth. Multiplication is by simultaneous or succes- 

 sive fissions, producing chains of daughter individuals. The tomite has 

 a buccal ciliature and a buccal orifice, but no rosette. It is believed that 

 a crab may be involved in the cycle. Opdinopsis occurs in the liver and 

 intestine of cephalopods, and one species has been found in the liver 

 of the pelagic gasteropod Carhiaria mediterranea. 



