120 BASAL GRANULE OF FLAGELLUM 



by the Hypermastigida and the basal granules of the cilia of Ciliophora, 

 which are to all intents and purposes blepharoplasts, is still more difficult 

 to answer. 



Another point in connection with the blej)haroplasts of flagellates 

 must be mentioned. Many observers have described fibres which connect 

 the blepharoplasts with the karyosome of the nucleus, and they suppose 

 that these fibres represent centrodesmoses which were formed when the 

 supposed intranuclear centriole divided off the blepharoplasts. As 

 already remarked, when several blepharoplasts are present, they are 

 usually packed so closely together that they cannot be distinguished 

 individually. It not infrequently happens, however, that in certain 

 individuals of any species of flagellate the blepharoplasts are more dis- 

 persed, so that it is possible to recognize the actual nvimber present. 

 Kofoid and Swezy (1920) have described a very complicated system of 

 fibrillar connections between the various blepharoplasts of Chilomastix, 

 and they introduce into their scheme a definite centrosome which they 

 state is present upon the nuclear membrane and is connected by a fibre 

 with one of the blepharoplasts (Fig. 69). If such a centrosome and 

 system of fibres is present in this flagellate, it has at any rate escaped 

 detection by most observers. The complicated system of fibres which 

 they describe as being present, together with the karyosome, centrosomes, 

 blepharoplasts, flagella, and other motor organs and marginal filaments 

 of the cytostomal groove, they name the neuromotor syste?n. This term 

 has been extended by them to include the fibrillar structures which occur 

 in other flagellates, such as the complex organisms parasitic in termites, 

 while Sharp (1914) employs it for the fibrillar apparatus of the ciliate 

 Diplodinium ecaudatum (Fig. 520). It is quite possible that some of the 

 fibres have a motor function, but others appear to be merely supporting 

 rods, while there is at present no direct evidence to prove that they are 

 comparable to nerve fibrils which the name neuromotor suggests. In 

 using the term " neuromotor system," groups of structures which are not 

 necessarily homologous in different organisms have been united under 

 one name. Kofoid and Swezy, for instance, homologized one of the 

 fibres which support the margin of the cytostome of Chilomastix, the 

 basal fibre of the undulating membrane in Trichomonas, and the two 

 structures of unknown function which commonly occur in the posterior 

 region of Giardia as parabasals. There seems to be no real evidence that 

 these are in any way homologous with the true parabasals of other flagel- 

 lates, and it is worthy of note that several observers have described what 

 are probably true parabasals in certain species of Trichomonas. 



The growth and the formation of new flagella are intimately bound 

 up with the activities of the blepharoplast. When the blepharoplast of 



