350 Ciliophora 



Fig. 7. 9. A. BuxtoneUa sulcata Jameson (after Rees): somatic ciliation, 

 nuclei, groove leading to the posterior cytostome; x225. B. Longitudinal sec- 

 tion of posterior end of B. sulcata, showing cytostome and gullet; x5I0 

 (after Rees). C, D. ColUnella gundii Chatton and Perard (after C. & P.): C. 

 Ventral view showing preoral groove, nuclei, ectoplasmic and endoplasmic 

 zones separated by a layer of myonemes, xl25. D. Optical parasagittal sec- 

 tion, posterior end of body, showing cytostome, gullet, and contractile vacu- 

 ole, x275. E-G. Nicollella ctenodactyli Chatton and Perard (after C. & P.): 

 E. Ventral view showing preoral groove ending at the cytostome, the nuclei, 

 contractile vacuole, thick anterior zone of ectoplasm, and layer of myonemes; 

 xl25. F. Cross-section between cytostome and anterior pole, showing preoral 

 groove and layer of myonemes separating ectoplasm and endoplasm; x240. 

 G. Cross-section through cytostome and pharynx, x240. H. Pycnothrix mono- 

 cystoides Schubotz: the groove follows a slightly spiral course down one side 

 to the posterior pole and then up on the other side almost to the anterior 

 pole; in each groove, a number of pits which serve as cytostomes; x35 

 (after Chatton and Perard). 



