344 Ciliophora 



hirtus contains calcium carbonate and apparently is covered by an organic 

 pellicle (65). Calcification of the plates is inhibited by exposure of the 

 ciliates to benzenesulfamid (67). A ring of circumpharyngeal trichites 

 (Fig. 7. 4, B, G) is characteristic. Although the Colepidae sometimes ingest 

 small algae, they are primarily carnivorous. 



Fig. 7. 5. A, B. Mesodinium acarus Stein (after Noland), lateral view, 

 xl400; anterior end, showing oral tentacles, x2800. C-E. Didinhim nasutum 

 O. F. M., 80-150^: C. General organization (after Kahl). D. Freshly excysted 

 specimen, ciliation more extensive than in the adult; x450 (after Beers). 

 E. Schematic longitudinal section; endoplasmic fibrils, circumpharyngeal 

 trichites, macronucleus, contractile vacuole (after ten Kate). F, G. Askenasia 

 volvox (Claparede and Lachniann) Kahl, anterior and lateral views, x630 

 approx. (after Wang and Nie). H. Cyclotrichium gigns Faurc-Fremiet, speci- 

 men 160x250^; schematic (after F-F.). I. Trochilia marina Mereschkowsky, 

 x850 (after Kahl). J. Dysteria navicula Kahl, x650 (after Wang and Nie). 

 K. Hartmannula entzi Kahl, x460 (after Wang). 



