206 H. M. WOODCOCK. 



wide spindle (fig. 33 a and d). In the case of other Avian 

 Trypanosomes, whose life-cycle has not yet been worked out, 

 the parasites have generally been given distinct names 

 according to their appearance when observed. Thus, the 

 attenuated or " spirochagtiform " type is exemplified by T. 

 johnstoni (fig. 51) from a small bird (Bstrelda) in Sene- 

 gambia; while the broad fusiform type is represented by 

 Hanna's Trypanosome from Indian birds, and particularly by 

 Dutton and Todd^s parasite (also from Estrelda), which is 

 almost rhomboidal in shape (fig. 52). According to Laveran's 

 figure, T. avium (fig. 16 p) occupies an intermediate position. 

 Novy and McNeal find, however, considerable polymorphism 

 in this species, and include herein some of the above forms. ^ 



No one doubts that the anterior extremity of the body in 

 the biflagellate or Heteromastigine forms (Trypanoplasma 

 and Trypanophis) is that from which spring the two 

 flagella. In these the anterior end may be acutely or obtusely 

 conical (fig. 17 r) or bluntly rounded (figs. 17 G, 18 a and c). 

 At the tip is often to be noted a little active (" metabolic "), 

 sensitive beak or rostrum ; although this points to one side 

 in Trypanophis, it is probably morphologically terminal. 

 Equally certain is it that in the uniflagellate form Trypano- 

 morpha (Trypanosoma) noctuse, whose life-cycle has 

 been described above, the end of the body bearing the free 

 portion of the flagellum is the anterior one. But with regard 

 to the correct orientation in the rest of the uniflagellate 

 Trypauosomes (collectively included in the genus Trypano- 

 soma), the greatest confusion exists. At present,^ for the 

 sake of clearness, the terms flagellate and non-flagellate end 

 will be used. 



In Trypanosoma the non-flagellate extremity presents 

 considerable variation, often in different individuals of the 



' It is uncertain how far the conclusions o£ these authors are warranted, 

 since their " determinations " appear to have been based largely on the 

 different forms of the parasites observed in cultures. See, however, below, 

 in Systematic Section. 



The whole question is fully discussed in Section 11. 



