32 THE BIOLOGY OF STENTOR 



connection is a smooth one, fibrils from the end fiber bending and 

 running into the basal fiber. Photographic evidence of these points 

 is very convincing. The whole basal structure of the membranelle 

 extends for about 20/x into the endoplasm. 



cdi 



hineiosome 



Ciliary roois 



membranelle 



memhranelLar hand 



inke r memhranelUr 

 connecliye 



jfooz bundle 



Jbasal liber 



Fig. 5. Structure of membranelles as revealed by electron micro- 

 scopy. (After Randall and Jackson, 1958.) 



The function of this intracellular structure of the membranelles 

 has been variously interpreted as contractile, nutritive, supportive, 

 or coordinating, beginning with Brauer (1885) who thought the 

 basal fiber a muscle which contracted the whole frontal field. 

 Maier (1903) modified this view with a speculation that the basal 

 lamellae retract or pull the membranelles inward while the basal 

 fiber draws them together; but the membranelles do not seem to 

 retract, and were the basal fiber contractile it would only pull the 



