PROTOZOA AND OTHER ANIMALS 937 



Other habitats than the mantle cavity of Pelecypoda have been adopted 

 by various species of Anci struma and Boveria, as well as by members of 

 other genera. Thus Issel (1903) found A. cyclidioides on certain chitons 

 and gasteropods {Natica heraea) as well as on Pelecypoda; and he de- 

 scribed A. barbatum solely from gasteropods of the genera Fusus and 

 Murex. Adaptation to these hosts is, as was stated above, probably second- 

 ary. In a similar manner, one species of Boveria, the type species B. sub- 

 cylindrka Stevens, is attached to the membrane of the respiratory tree of 

 the holothurian Stic ho pus calijornicus (Stevens, 1901). So similar to 

 this, however, that it has been classified as a variety of the same species, 

 B. s. var. concharum Issel, is a Boveria that occurs on the gills of ten of 

 fourteen Pelecypoda that harbor Ancistrumidae at Naples (Issel, 1903). 

 B. labialis lives in the respiratory trees of holothurians as well as on the 

 gills of a clam (Ikeda and Ozaki, 1918). 



Eupoterion pernix, which has many characteristics of a species of 

 Ancistruma, inhabits the intestine of the limpet Acmaea persona (Mac- 

 Lennan and Connell, 1931). The aberrant Hemispeira asteriasi Fabre- 

 Domergue (1888) znd Hemispeiropsis antedonis (Cuenot, 1891) occur 

 on echinoderms, the former on the dermal branchiae of a starfish, and 

 the latter on the pinnules of a crinoid (Cuenot, 1894; Konig, 1894). 

 Protophrya ovicola Kofoid occurs upon the surface of the egg capsules 

 in the brood sac of the gasteropod Littorina rudis; and Isselina intermedia 

 is found in the mantle cavity of Littorina obstusata. The two latter 

 species, at least Protophrya, are more truly parasitic than other Ancis- 

 trumidae, and they have undergone some retrogressive changes. 



For the most part, Ancistrumidae feed on bacteria, diatoms, and 

 other material extracted from the currents of water. Issel (1903) noted 

 that two bivalves constantly rich in the ciliates, Capsa fragilis and Tellina 

 exigua, live under conditions most suitable for offering their inquilines 

 copious food. They occur in calm, muddy water, rich in organic sub- 

 stances. The diet of plankton organisms may be supplemented by 

 sloughed-off epithelial cells, as noted by Stevens (1901) in Boveria 

 subcylindrica and Pickard (1927) in B. teredinidi. The account by Ikeda 

 and Ozaki (1918) of tissue invasion by B. labialis is not acceptable 

 without corroboration. The changes said to be undergone by the encysted 

 ciliate within the tissue are bizarre. 



Protophrya ovicola in the brood sac of Littorina has a destructive 

 chemical action upon the eggs (Kofoid, 1903) and a teratogenic action 



