360 Ciliophora 



Only two genera have been recognized; Maryna Gruber (102; Fig. 7. 15, C, D) and 

 Mycterothrix Lauterborn (102; Fig. 7. 15, E). 



Family 9. Paraisotrichidae. The mouth is subterminal, opening just 

 posterior to the concretion-vacuole. The somatic ciHation is complete and, 

 except for an anterior tuft of longer cilia, is uniform. 



This family was erected by Hsiung (91) for Paraisotricha Fiorentini (Fig. 7. 15, A; 

 B), several species of which have been reported from the cecum and colon of horses. 



Family 10. Parameciidae. An oral groove (Fig. 7. 16, A-L) extends from 

 the anterior end toward the middle of the body. The somatic ciliation is 

 complete and essentially uniform. The adoral ciliature includes a differ- 

 entiated dorsal zone of long cilia ("quadripartite membrane" of von 

 Gelei) and a penniculus (76, I3-i), a dense band of cilia which extends 

 in a shallow spiral toward the cytostome (Fig. 7. 16, D, M). 



In addition to the genus Paramecium Hill (107. 218; Fig. 7. 16, E-L), Kahl (102) has 

 referred his genus Physalophrya to this family. On the basis of general similarities in 

 the adoral ciliature of Paramecitini and Espejoia, Faine-Fremiet (62) has suggested the 

 possible transfer of the genus Paramecium to the Hymenostomina. 



Family 11. Plagiopylidae. These are dorso-ventrally flattened ciliates 

 with a central peristomial groove which lies in the anterior half of the 

 body and extends more or less transversely from the right margin toward 

 or past the sagittal plane. A dorsal non-ciliated striated band, represent- 

 ing a thickened strip of the pellicle, occurs in Lechriopyla and Plagiopyla 

 (Fig. 7. 17, F, J). The functional significance of this band is unknown. 

 The somatic ciliation is otherwise complete. A ciliated cytoproct has been 

 reported in Lechriopyla (137). 



The family includes the following genera: Lechriopyla Lynch (137; Fig. 7. 17, J), 

 containing an intestinal parasite of sea-urchins; Plagiopyla Stein (101, 102, 137; Fig. 

 7. 17, F-H), including ciliates from fresh and salt water; Sonderia Kahl (101, 102, 113; 

 Fig. 7. 17, I) and Sonderiella Kahl (102), both represented in salt water. 



Family 12. Spirozonidae.The family includes Spirozona Kahl (102, Fig. 

 7. 15, F). A band of closely set cilia extends from the peristome posteriorly 

 and spirally to the right surface of the body. In addition, the tapering 

 posterior end bears a tuft of caudal bristles. Otherwise, the somatic cilia- 

 tion is uniform. The only described species occurs in fresh water and 

 feeds on bacteria. 



Fatnily 13. Trichopelmidae. These laterally compressed ciliates have a 

 firm pellicle which usually shows a few longitudinal ribs and grooves, the 

 latter sometimes limited to the left surface. The semicircular or crescentic 

 dorsal margin is smooth in outline. The mouth may lie near the anterior 



