82 BIOLOGY OF THE PROTOZOA 



The silver line systems then are definite aggregates of granules 

 and fibrils which, in some pattern or other, form a part of the 

 cortex of every ciliate. It is present over large stretches of the 

 cell body, even where cilia are absent; for example, throughout the 

 surface of a Vorticella. In Suctoria and in some ciliates (e. </., 

 Foettingeriidae) it persists after the embryonic cilia have entirely 

 disappeared, hence to Chatton and Lwoff (1929) the silver line 

 system may have a palingenetie significance, and they term it the 

 infraciliature. 



The silver line system appears to be, like the nucleus, a definitely 

 organized part of the fundamental organization. It forms a con- 

 tinuum over the cell and persists from generation to generation by 

 division. Cortical structures are formed, apparently under its 

 influence (see Fig. 43) and it may well be a mechanism whereby 

 coordination is effected throughout the organism (see Klein, 1928, 

 1929, 1930). 



