Ciliophora 401 



ventral cirri, there are bands and tufts of free cilia. The genus is rep- 

 resented by a single marine species. 



Euplotaspis Chatton and Seguela (34; Fig. 7. 39, G) resembles Paraeuplotes in several 

 respects and possibly belongs in the same family. There seem to be two ventral rows of 

 free cilia, and the frayed compoinid organelles in the frontal field may be homologous 

 with the tufts of cilia in Paraeuplotes. 



Suborder 6. Ctenostomina 



These are small laterally compressed, wedge-shaped ciliates in 

 which the base of the wedge (Fig. 7. 42, B) represents the ventral (oral) 

 surface. In lateral view (Fig. 7. 42, C, H), the dorsal margin usually 

 describes about a third of a circle but may approach a semicircle or almost 

 a circle. Anteriorly, the dorsal keel ends in a brow-like prominence or in 

 a spur or spine (Fig. 7. 42, E, H, J). Except for the ventral surface, and 

 the posterior end in certain species, the body is covered with a firm 

 pellicle differentiated into longitudinal plates (105). 



The somatic ciliation is much reduced. On the left surface there are 

 typically four rows, extending forward for varying distances from the 

 posterior end (Fig. 7. 42, F, J), and also a fifth frontal row (exception- 

 ally, two frontal rows) extending posteriorly for some distance from an 

 origin near the anterior pole. In primitive species, a frontal band of five 

 rows arises anteriorly on the lower left surface, extends across the narrow 

 ventral surface, and then upward and posteriorly for some distance on 

 the right side. A tvift of preoral cilia anterior to the peristome, and two 

 adoral rows running from the frontal band almost to the peristome, may 

 also be found on the ventral surface. Modifications of the general pattern 

 occur in the more specialized types. 



The peristome is a ventral pouch covered on the left by a thin wall 

 (Fig. 7. 42, A, B) apparently analogous to the "oral lip" of various 

 Spirotrichida. In contrast to most Spirotrichida, the adoral membranelles 

 are reduced to eight in the peristome proper and a small ninth one in 

 the pharynx (105). 



All except two species are known from fresh water and all are sapro- 

 pelic (or polysaprobic) types, growing well in the presence of putrefying 

 materials. Kahl (105) recognized three families. 



Family 1. Epalcidae. The posterior end of the body is unarmored, al- 

 though surrounded by the spurred or spiny ends of the armor plates. 

 Somatic ciliation is relatively complete. On the left, a frontal band and 

 the four primitive posterior rows are always present. On the right side 

 of the body, at least the ventral and dorsal rows are present. 



Three genera are listed for this family (105): Epalxis Roux (Fig. 7. 42, A, D), 

 Pelodinium Lauterbom (Fig. 7. 42, F), and Saprodinium Lauterborn (Fig. 7. 42, J). 



