CYTOLOGY 



325 



constancy, and, if present, it has been overlooked by the majority of 

 competent observers. The complicated system of fibres associated with 

 the nuclear changes and divisions of Trypanosomu noctuce and its develop- 

 ment in the owl and mosquito, as described by Schaudinn (1904), are 

 only of historic interest. 



An axial filament was described in Herpetomonas muscarum from the 

 fly Calliphora erythrocephala by Alexeieff (1911e). He also observed in 

 this fly the peculiar Rhynchoidomonas forms first described by Patton 



Fig. 155. — Herpetomonas muscarum from Intestine of Calliphora erythrocephala 



(x 1,500), ARRANGED TO SHOW AlEXEIEFF'S ViEW OF THE ORIENTATION OF 



THE Rhynchoidomonas Forms. (After Alexeieff, 1911.) 

 1. Typical leptomonas. 2. Leptomonas with rhizostyle. 



3-4. Axoneme of flagellum still visible, while rhizostyle is more marked. 

 5-6. Axoneme no longer visible, while rhizostyle is well developed. 



7. Dividing form. 

 It appears j/robable. however, that the forms at 3-7 should be reversed, and that the structure 

 called the rhizostyle is in reality the attached axoneme, which is longer owing to the back- 

 ward migration of the kinetoplast. 



(1910a) in Lucilia (Fig. 155). In the latter there is a deeply staining 

 line running from the kinetoplast along the surface of the body past 

 the nucleus to the pointed extremity of the body. The other extremity 

 is drawn out into a tapering process. In some of these forms there 

 is to be detected a faintly staining line extending from the kinetoplast 

 to the end of this process. The natural interpretation of this appear- 

 ance would be that the deeply staining band is the axoneme, and 

 that the flagellates have the trypanosome structure, though a some- 

 what remarkable one. Alexeieff, however, interprets them differently. 



