Ciliophora 379 



Contractile vacuoles — or sometimes a contractile canal (15, 147) as in 

 Haptophrya (Fig. 7. 26, J) — are generally present. There may be one 

 contractile vacuole or, at the other extreme, many vacuoles arranged in 

 one or more longitudinal rows (Fig. 7. 26, L, O). 



Little is known about the life-cycles of Astomina. Most species are 

 known from oligochaetes; a few, from amphipod Crustacea and from the 

 digestive tracts of Turbellaria and Amphibia. Reproduction may involve 

 typical binary fission, fission in which one daughter organism is a little 

 smaller than the other, or consecutive fissions leading to the production 

 of chains (Fig. 7. 26, A-F). In some chains both the anterior (primite) 

 and the posterior (satellite) organisms undergo repeated fission; in others, 

 the primite produces several satellites without undergoing a reduction in 

 size. 



The families described below represent five of the six recognized by 

 Cheissin (36). Other workers have subdivided the Astomina in somewhat 

 different fashion. 



Family 1. Anoplophryidae. The body may be ovoid or distinctly elon- 

 gated and the cilia are arranged in longitudinal rows. A poorly developed 

 sucker is commonly present but skeletal elements are typically absent. 

 There may be one, two, or more contractile vacuoles, or sometimes none. 



Cheissin (36) has assigned the following genera to the family: Anoplophrya Stein 

 (41, 84, 201; Fig. 7. 26, I), BiltschUeUa Awerinzew (84; Fig. 7. 26, G, H), Dogielella 

 Poljansky, Herpetophrya Siedlecki, Kofoidclla Cep^de, Metaphrya Ikeda, Orchitophrya 

 CepMe, Perezella Cepcde, Perseia Rossolimo (181; Fig. 7. 26, L), Protoanoplophrya 

 Mijaschita, Rhizocarium Caullery and Mesnil. 



Family 2. Haptophryidae. A long contractile canal, instead of separate 

 contractile vacuoles, is characteristic. An antero- ventral sucker is present 

 in some species. Spicules or hooks may or may not be present at the 

 anterior end. 



The following genera have been referred to the family: Haptophrya Cep^-de (15, 

 147, 225; Fig. 7. 26, J, R), Laclnimnnelln CepMe and SteineUa Cepcde. 



Family 3. Hoplitophryidae. These Astomina are ec[uipped with a hold- 

 fast apparatus, longitudinal supporting spicules, or both types of struc- 

 tures. There may be several to many contractile vacuoles. 



The family includes the following genera: Buchneriella Heidenreich (84; Fig. 7. 26, 

 M, N), Hoplitophrya Cepcde (85; Fig. 7. 27, K), Mesnilella CepMe (36, 84, 183; Fig. 7. 

 27, H-J), Metaradlophrya Heidenreich (5, 84; Fig. 7. 26, O, P), Mrazekiella Kijenskij 

 (36, 84; Fig. 7. 27, F, G), Protoradiophrya Rossolimo (36, 183; Fig. 7. 27, D, E), Radio- 

 phrya Rossolimo (36, 183; Fig. 7. 27, A-C). 



Family 4. Intoshellinidae. These are elongated ciliates with longitudinal 

 or spiral rows of cilia. There is a holdfast apparatus in the form of a 



