224 



INTRODUCTION TO CYTOLOGY 



figure, a paradesmose being drawn out between them. Apparently, 

 one or two of the free fiagella accompany the new blepharoplast, new ones 

 later growing out to restore the full number. It is also accompanied 

 by a new chromatic basal rod, which begins to differentiate as a row of 

 granules even before the division of the original blepharoplast (Wenrich, 

 1921). 



In the trypanosomes, as in the infusoria, there are two nuclei: the 

 trophonucleus and the kinetonucleus. Motor mechanisms differ con- 

 siderably within the group, but it seems that the flagellum is usually borne 



•te- 





A B C 



Fig. 137. — A, B, ciliary mechanism in Lampsilis. The cilia (c) are fusrd in pairs at 

 their tips. Below the basal corpuscles (6) in the cuticle each cilium splits into two strands 

 which connect with strands from other basal corpuscles. (After Grave and Schmitt, 1924.) 

 C, diagram of a ciliated epithelial cell based on the figures of Saguchi (1917). 



on a basal granule (centrosome?) associated with the kinetonucleus. At 

 the time of cell-division the trophonucleus, kinetonucleus, and basal 

 granule all divide. Although it was formerly thought that the flagellum 

 also split, it now seems clear that it remains attached to one half of the 

 divided basal granule while a new one arises from the other half.^^ 



In ciliated epithelial cells each cilium is associated with a basal 

 corpuscle in or near the cell membrane (Fig. 137). The nature of such 

 basal granules has been the subject of a long controversy beginning with 

 the statement of the theory that they, like the granules bearing the axial 

 filament in the spermatozoon, are modified centrioles or centriole deriva- 



28 Rosenbusch (1909), Kuczynski (1917), Hartmann and NoUer (1918). 



