CILIATES 187 



larvae but has not been studied with the electron microscope. 



Rudzinska's study of the contractile vacuole region in Tokophrya 

 showed that a group of cilium-less kinetosomes was always 

 present near the pore of that organelle. An invagination of the 

 pellicle marking the beginning of brood pouch formation 

 appeared next to this kinetosome field. Pottage (1959) states that 

 scattered kinetosomes are present in the ectoplasm of adults of 

 Discophrya piriformis. They also are seen in the brood pouch wall, 

 and of course in the ciliated larva. No trace of associated kineto- 

 desma or other fibrils was observed by him. However, one of 

 Rudzinska's (1958) micrographs of the kinetosome field in the 

 Tokophrya adult shows distinct connecting fibrils. From Pottage's 

 description, the cortex of the adult Discophrya seems to resemble 

 that of Ephelota. Tentacles are reported to contain 25 to 30 fibrils 

 arranged in ten groups of two or three each, forming the wall of 

 the internal canal, which continues deep into the cell body. The 

 larva has in its cytoplasm tubes similar to these intracytoplasmic 

 portions of the tentacle canal, and Pottage suggests that tentacles 

 develop during metamorphosis by outgrowth from these tubes. 



Mitochondria in the suctorians are of typical microtubular 

 construction. Elements of the cytoplasmic matrix are conven- 

 tional, but no Golgi bodies have been found. Rudzinska (1958) 

 showed peculiar stacks of very small, somewhat inflated, mem- 

 branous discs that occurred commonly through all parts of the 

 cell; if these were flatter they would resemble minute dictyosomes. 



Attachment of the adult suctorian to a substrate may be by 

 means of a stalk terminating in a firmly adhesive disc. Rudzinska 

 and Porter (1954a) found the intact dried disc to consist of a 

 rootlike mass of branching fibrils, the finest unit apparently 

 aboutl5m/x. Larger branches appeared to be formed of bands or 

 cables of finer units. 



Order Chonotrichida 



Only a single report in the electron-microscope literature deals 

 with ciliates of the Order Chonotrichida. Like the suctorians, 

 these ciliates are sedentary as adults, with a reduced somatic 

 ciliature, and have ciliated migratory young. The adult attaches 

 to the substrate frequently by means of a non-contractile stalk, 

 which in Chilodochona (Faure-Fremiet, Rouiller, and Gauchery, 



