STUDIES .ON AVIAN H^MOPROTOZOA. 675 



Rovigiio, the parasites which showed it being also of the 

 same type of form. 



There is still another variety of form to be mentioned, 

 which occurs in case A (in the bone-marrow). This is a 

 fairly small trypanosome (figs. 55 and 50), which is very 

 narrow in proportion to its length. The aflagellar end is 

 comparatively long and finely drawn out, and may approach 

 the attenuated condition. The flagellum is fairly short, and 

 the undulating membrane has well-developed folds. The 

 dimensions of the individual in fig. 55 are: total length, 27/x, 

 breadth (including membrane), 3 /,<, and length of flagellum 

 6| ju. The kinetonucleus is relatively large. These parasites 

 strongly resemble in appearance young ordinary or definitive 

 trypanosomes. 



With regard to the multiplication of these small forms the 

 only evidence I have been able to obtain is very slight. 



I have observed three or four individuals (and not more) 

 of the wide stumpy kind from case A, in which the kineto- 

 nucleus is in two parts (figs. 48 and 54) ; and in one solitary 

 instance, just alluded to, the flagellum is partially doubled. 

 In no case have I seen two trophonuclei. The condition in 

 fig. 48 is the nearest approach to trophonuclear division that 

 I have observed ; this may represent commencing division 

 because other organellas of this parasite are dividing. The 

 flagellum has not yet begun to divide, but as a prelude thereto, 

 the centrosomic granule at its proximal end ("blepharoplast ") 

 is clearly double. So far as the fusiform series (of the other 

 case) is concerned, I have observed absolutely no signs of 

 division at any phase. 



G-eneral Remarks. — The significance and relation to 

 each other of all these manifold forms of the trypanosome is 

 a somewhat difiicult question. Where transitional forms 

 or division phases occur they afford, of course, consider- 

 able help. Beginning with the small forms, the stumpy 

 parasites of case A, in which indications of division can be 

 found, probably give rise, as a result of that process, to small 

 individuals like those in figs. 46 and 47, which grow into 



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