62 STRUCTURE 



perhaps smaller, granule is also present on the peripheral fibrils 

 near the middle of the basal body. Solid strands run between 

 adjacent basal bodies at their inner ends and near the middle to 

 connect adjacent granules at the same level (PL IVb). A similar 

 structure is reported for the membranelles of Nyctothenis (King, 

 Beams, Tahmisian and Devine, 1961). All the component cilia 

 of each cirrus and membranelle are thus firmly linked together 

 at a '* basal plate." The inner termmal granule of the basal 

 body fibrils may also be used for the attachment of other types of 

 root. 



Several strata of structures of fibrillar appearance are revealed 

 in the surface layers of many ciliates by the silver impregnation 

 technique (e.g. Klein, 1928; von Gelei, 1932; Parducz, 1957, 

 1958a; see references in Corliss (1961) to many others). Ehret and 

 Powers (1959) found that the ** chicken-wire " lattice systems of 

 Paramecium sho\^Ti up by this technique are, in fact, parts of the 

 pellicular corpuscles, flattened vesicular structures which are 

 packed together to cover the surface of the animal. The fibrils 

 connected to the basal bodies lie internal to these *' silverline " 

 lattice systems. Ehret and Powers found only the striated kine- 

 todesmal fibres in this position, but Pitelka (1961) found also 

 groups of unstriated fibres associated with the kinetosomes of 

 tetrahymenid ciliates. 



The cilia of Paramecium occur in rows or kinetics, and their 

 basal bodies are connected together within the row by the 

 kinetodesmata. Chatton and Lwoff (1935) found that the 

 kinetodesmata alwa3^s run along the right (i.e. the animal's right) 

 side of the row of kinetosomes (basal bodies), and they proposed 

 the " rule of desmodexy," which seems to be consistent. Thus, 

 at the surface of Paramecium, a kinetodesmal fibre with a striation 

 period of 350 to 400 A leaves each kinetosome (or the posterior 

 member of a pair on some parts of the body surface), and runs 

 out to the right before turning forward to join other kinetodesmal 

 fibres in the kinetodesmal bundle. Throughout their length these 

 fibres run more or less parallel to the body surface. Each kineto- 

 desmal fibre extends along the kinetodesma to about the fifth or 

 sixth cilium in front, tapering throughout most of this length from 

 an initial diameter of 1200 A to a point at the end (Metz, Pitelka 

 and Westfall, 1953; Sedar and Porter, 1955). Within the bundle 



