378 Ciliophora 



A number of the Astomina have developed holdfast organelles. Such 

 structures usually lie at or near the anterior pole which is often in con- 

 tact with an epithelium of the host. An antero-ventral sucker (Fig. 7. 

 26, J, K) is characteristic of certain intestinal species. In various other 



'MM 



Fig. 7. 27. A, B. Holdfast apparatus of Radiophrya lumbrici Cheissin, 

 ventral view (A), sagittal section through anterior end of body (B), x650 

 (after C). C. Radiophrya hoplites Rossolimo, primite with three satellites; 

 xlOO (after Cheissin). D, E. ProtoradiopJirya fissispiciilata Cheissin, primite 

 and satellite (D), x375; tangential section of anterior end (E), showing 

 spicules, x975 (after C). F, G. Mrazekiella intermedia Cheissin: entire spec- 

 imen (F), x240; holdfast apparatus (G), x975 (after C). H-J. Mestiilella 

 miiltispiculata Cheissin: ventral view (H) showing nuclei, skeletal spicides 

 and row of contractile vacuoles, x210; transverse sections near anterior ends 

 (I) and near posterior ends (J) of the spicules, xl650 (after C). K. Anterior 

 end of HopUtophrya secans Stein, showing skeletal apparatus; x900 (after 

 Heidenreich). 



Astomina the anterior end is equipped with an apparatus composed of 

 barbs or spicules (Figs. 7. 26, N, P; 27, B, K; 28, C, G). In addition, skeletal 

 fibrils of unknown function may extend for some distance near the sur- 

 face of the body (Fig. 7. 27, H-J) and sometimes pass from the cortex 

 into the endoplasm (183). 



