420 Ciliophora 



in which the two conjugants eventually separate much as in ciliates (156), 

 complete fusion and the production of a single synkaryon have been 

 reported in Lernaeophrya capitata (79). 



Encystment is known in a number of species. In Tokophrya leinnarum 

 (156), encystment involves the deposition of a transparent secretion, at 

 first basally, and finally over the apical end of the body. Specimens in 

 early encystment resemble certain of the loricate Suctorea. Precystic with- 

 drawal of the tentacles has not been observed. Instead, these structures 

 remain matted over the apical surface and are engulfed by the material 

 secreted to form the cyst membrane. 



Taxonomy 



The Suctorea, which are probably more closely related to the gymno- 

 stomatous Holotrichida than to other ciliates (62, 103), seem to have 

 undergone little basic diversification in the course of their evolution. Since 

 there seems to be no logical basis for differentiating orders, the group has 

 usually been divided into a number of families. Even this simple arrange- 

 ment might be more satisfactory if some of the families v.ere more sharply 

 defined so as to take care of genera Vvhich show apparently intermediate 

 combinations of characteristics. Perhaps a more intensive study of life- 

 cycles, with detailed comparisons of the migratory larvae, might yield 

 useful information. For example, it is interesting that larvae of Podophrya 

 soliformis and Parapodophrya denticulata (Family Podophryidae) have 

 been described with a polar circlet of cilia similar to that reported for 

 Discophryn cybistri (Family Discophryidae); the larva of Podophrya sandi, 

 with an equatorial belt of cilia resembling that noted in species of Toko- 

 phrya (Family Acinetidae); larvae of Podoplirya globidifera, P. fixa, and 

 P. parasitica, with ciliary rows w'hich parallel the long axis of the body 

 instead of encircling it transversely. 



Family 1. Acinetidae. This family is characterized by endogenous bud- 

 ding and by the possession of capitate tentacles, usually arranged in 

 groups. A lorica is often present, and a stalk may be present or absent. 



The following genera have been included in the family: Acineta Ehrbg. (148, 206; 

 Fig. 7. 52, A, H), Acinetides Swarczewsky (206; Fig. 7. 52, E), Acinetopsis Robin (206; 

 Fig. 7. 52. D), AUantosoma Gassovsky (90; Fig. 7. 53, G), Anarma Goodrich and Jahn 

 (80; Fig. 7. 53, E), Dactylophrya Collin (40), Endosphaera Engelmann (138; Fig. 7. 

 53, .\-D), Multijasciculatum Goodrich and Jahn (80; Fig. 7. 52, B), Paracineta Collin 

 (40), Poitsia Chatton and Lwoff (23), Pseudogemma Collin (40), Soleiwphrya ClaparMe 

 and Lachmann, Squalophrya Goodrich and Jahn (80; Fig. 7. 53, H, I), Tachyblaston 

 Martin (148), Thecacineta Collin (206; Fig. 7. 52, G), Tokophrya Biitschli (156, 206; 

 Fig. 7. 52, C), Tokophryopsis Swarczewsky (206; Fig. 7. 52, F). 



Family 2. Dendrocometidae. These stalkless forms undergo endogenous 

 budding. Capitate tentacles may be distributed over the surface or local- 

 ized on slender extensions of the body. 



