128 



BIOLOGY OF THE PROTOZOA 



nemes but coordinating fibrils. It is conceivable, moreover, that 

 myonemes in a generalized condition may be both coordinating 

 and contractile in function. In some cases, however, two distinct 

 sets of fibrils have been observed, one of which is interpreted as 

 contractile, the other as conductile. Thus Xeresheimer described 

 "myophanes" and "neurophanes" in Stentor coeruleus, and Clima- 

 costomum virens, the former extending the entire length of the 

 body, the latter only from the base to the center (Fig. 71). On 

 a priori grounds it would seem that, as Yocom points out, Neres- 



,11'^i 



%!-'- 



Fig. 71. 



■Climacosiomum sp. To show neurophanes (NE) and myophanes (MY). 

 (Original.) 



heimer made an unfortunate application of his two terms, his 

 neurophane fibers, for example, to which lie ascribes a transmitting 

 function, being situated in the least advantageous position for the 

 functions of irritability or conductility, Jennings having shown that 

 the first and most strongly marked reactions to certain stimuli in 

 ciliates appear in the anterior region, a result confirmed by Alverdes 

 (1922). 



The more recent observations of Sharp, Yocom, and Taylor, all 

 from Kofoid's laboratory, afford more striking evidence of specific 

 conducting or coordinating fibrils in ciliates, although not connected 



