THE INFUSORIA 461 



4. Podophryidce. Stalked or sessile, with no house and with numerous 

 tentacles. Sphcerophrya, Podophrya (Fig. 190), Ephelota. 



5. Acinetidce. Stalked or sessile, with a house of simple form and wide 

 aperture, and with numerous tentacles, all knobbed. Tocophrya (Fig. 190), 

 Acineta (Fig. 10). 



6. DendrosomiddB (Trichophryidce). Sessile, without a house ; tentacles 

 knobbed, arranged in tufts or branches. Trichophrya, Dendrosoma, Lernceo- 

 phrya (Perez), Rhabdophrya (Chatton and Collin), Astrophrya (Awerinzew). 



7. Dendrocometidw. Flat forms with numerous branched arms on the ends 

 of which the suckers occur. Dendrocometes. 



8. Opkryodendridce. Marine stalked forms with numerous short tentacles 

 concentrated on proboscis-like processes. Vermiform individuals also occur 

 (p. 455). Ophryodendron. 



Affinities of the Acinetaria. The presence of cilia in the young stages, the 

 possession of distinct vegetative macronuclei and generative micronuclei, and 

 the process of conjugation, similar in all essential details to that of the Ciliata, 

 can leave no doubt as to the position of the Acinetaria in the class Infusoria, 

 and their affinities with the Ciliata. Collin, in a series of interesting studies, 

 has drawn attention to many points indicating a close relationship between 

 Acinetaria and Vorticellids, more especially the structural homologies between 

 the larvae of the one and the free-swimming stages of the other group ; for 

 example, the peritrichous arrangement of the cilia, the rudimentary adoral zone 

 at the posterior pole, and the fixation by means of a scopula-like organ at the 

 anterior polo, points especially well seen in the larva of Tocophyra cyclopum. 



Bibliography. For references see p. 502. 



