324 FAMILY: TRYPANOSOMIDiE 



the kinetoplast to another centrosomic body near the posterior end of the 

 flagellate (Fig. 154, 7). The writer (1913a) was unable to detect such a 

 filament in this flagellate. A similar filament (axoplast) was described 

 by Chatton and Leger, M. (1911), in Leptomonas (Herpetomonas) droso- 

 philce (Fig. 154, 1-5). It extended from the kinetoplast to the posterior 

 end of the body. When division was taking place it degenerated, and a 

 new one was formed between the two daughter kinetoplasts. At first 

 straight, it soon became U-shaped. The limbs of the U increased in length 

 till finally each was as long as the body, which meanwhile had commenced 

 dividing from its anterior end. When division of the body was complete, 

 the limbs of the U formed the new " axoplasts " of the daughter flagellates. 

 In Crithidia leptocoridis parasitic in the gut of the box-elder bug, Mc- 

 Culloch (1915) has described a system of fibres still more complicated 

 (Fig. 154, 6). In this case the " axostyle " commencing in the blepharo- 

 plast runs to the posterior end of the body, where it terminates in a granule 

 called the " chromatin granule." In addition, there is a fibre connecting 

 the blepharoplast or the kinetoplast with the karyosome of the nucleus, 

 and another (" myoneme ") running from the posterior end of the body 

 to terminate in the flagellum. In a subsequent work, however, the same 

 writer (1919) gives a diagram of C. lejJtocoridis which only shows one of 

 these fibres — namely, that connecting the blepharoplast with the karyo- 

 some of the nucleus. The majority of observers have not detected or 

 described these fibres in the flagellates they have examined. The writer 

 (1913a) has examined many forms which have been carefully fixed and 

 stained, and has seen no such structures present with the constancy which 

 would be expected if they were essential parts of the anatomy. If large 

 numbers of individuals of any species are examined, occasionally fibres 

 resembling those described by the various writers may be seen, but other 

 explanations of their presence can be given. Folds or creases in the peri- 

 plast or abnormally developed flagella may give rise to these appearances. 

 The whole group is such a homogeneous one that it is highly improbable 

 that structures so complicated would be present in one species and com- 

 pletely absent in another. 



A fibre connecting the blepharoplast or parabasal with the karyosome 

 of the nucleus has been more frequently described. McCulloch (1915) 

 refers to it as the rhizoplast, and not only mentions its occurrence in 

 Crithidia leptocoridis (Fig. 154, 6), but also (1917) in C. euryophthalmi 

 (Fig. 168), while Kofoid and McCulloch (1916) note it in Trypanosoma 

 {Herpetomonas) triatomw, a flagellate of the bug Neotoma fuscipes, Chagas 

 (1909) described a similar connecting fibril in the case of the developmental 

 forms of Trypanosoma cruzi in the bug Triatoma megista. 



Here, again, it may be said that this fibre has not been seen with any 



