932 



PROTOZOA AND OTHER ANIMALS 



In gregarines, the epimerite, which often is elaborately developed with 

 hooks or other appendages and inserted into the cell, may serve also 

 for absorption (see Watson, 1915). 



As regards ciliates, development of fixation habits and structures in 

 the holotrichous groups of Thigmotricha, Ptychostomidae, and Astomata 

 is discussed below. There is among heterotrichs a well-developed fixa- 

 tion apparatus in Licnophora (Stevens, 1901; Balamuth, MS). Urceola- 

 rids have an elaborately organized scopula, a cup-like apparatus 



Figure 198. Fixation apparatus of Cyclochaeta (Urceolar/a) korschelti. A, seen from 

 above, showing radially arranged ribs bent downward in hook-like points and ring com- 

 posed of overlapping, sickle-shaped individual pieces; B, cross section. (After Zick, 

 1928.) 



supported by radially arranged ribs and a ring of denticles (Fig. 197D; 

 Fig. 198) (see for description and illustrations, Zick, 1928, on Cyclo- 

 chaeta (Urceolar/a) korschelti; Fulton, 1923, on Trichodina pedi- 

 culus). As has been described in T. pedkulus on Hydra and Trkho- 

 dinopsh paradoxa in Cyclostoma elegans, the epithelial cells of the host 

 may be elevated into this sucker (Fig. 197C). A unique attachment 

 mechanism is that of Ellobiophrya donach, an inquiline of the gill 

 cavity of a lamellibranch. The posterior end of the body of this peritrich 



