CILIATES 169 



rows (kineties) that often become secondarily, in ontogeny or 

 phylogeny, modified by torsion, asymmetric growth, increase or 

 reduction in number, or incorporation of parts or entire rows 

 into a more or less elaborate buccal apparatus. Representatives 

 of the large Subclass Holotrichia bear (in at least some stages of 

 their life cycle) a fairly uniform covering of body, or somatic, 

 cilia; the buccal apparatus varies from extremely simple to rather 

 elaborate. In some adult holotrichs and in most orders of the 

 smaller Subclass Spirotrichia, the somatic ciliature is reduced 

 and/or modified into compound ciliary organelles; the buccal 

 apparatus in the spirotrichs always includes a spiraled adoral zone 

 of ciliary membranelles. 



In addition to the kinetosomes, a conspicuous feature of most 

 ciliates is a system, or systems, of cortical or subcortical linear 

 patterns that may in part be visible in living cells but are most 

 clearly revealed by staining techniques. These so-called fibrillar 

 systems are in general constant and species-specific. We shall see 

 that a number of quite different structural entities is included, but 

 it is necessary by way of introduction to review in the most general 

 terms the picture presented by light microscopy (for fuller details 

 see Gelei, 1936; Taylor, 1941; Klein, 1942; Wichterman, 1953; 

 Corliss, 1956; and Parducz, 1958a). Silver impregnation techni- 

 ques reveal the rows of kinetosomes and, typically, meridional 

 lines connecting them like beads on a string (Fig. 69, PL XIX). 

 Secondary silver meridians lacking kinetosomes also may be 

 present. Additional parts of these silverline systems may cross- 

 connect meridional lines or form networks between them. Other 

 fibers arising from kinetosomes and passing deeper into the cell 

 have been described, and a central body called the motorium or 

 neuromotor center is sometimes reported. Argentophilic patterns 

 associated with the buccal apparatus can become very complex. 



A particularly intriguing fibrous structure, usually not argento- 

 philic, is the kinetodesmos*, first described by Chatton and 

 colleagues in France (Lwoff, 1950). It is a fiber accompanying 



* This word, adapted to English via the French neologism cinetodesme, has 

 been variously employed in the singular and plural as kinetodesma-desmas ; 

 kinetodesma-desma; kinetodesma-desmata. In 1959 Ehret and Powers, on 

 sound etymological grounds, adopted kinetodesmos-desma, which usage 

 will be followed here. 



