THE HA k MO FLA GELLA TES 



these elongate, each accompanied by a double-nucleus, they take on 

 a trypaniform appearance, which is completed by the development 

 of a flagellum. Finally, the eight little male Trypanosomes (F, .v.r), 

 which are homologous with microgametes, break away from the 

 central residuum. These forms are apparently incapable of further 

 development in any way and soon die off. Schaudinn accounts for 

 this by the condition of the trophonucleus, which, he says, has 

 undergone reduction. 



The early stages in the formation of a female Trypanosome are 

 similar to those in the case of a microgametocyte. Here, however, 

 it is the eight small double- 

 nuclei, representing the 

 male constituents, which 

 degenerate, leaving the 

 large female nucleus to 

 become differentiated and 

 give rise to the locomotor 

 apparatus in the same way 

 as in an indifferent form 

 (Fig. 24, c). In the 

 females the flagellum, etc., 

 is poorly developed, and 

 the movements of the para- 

 sites are slow and feeble. 

 These Trypanosomes seem 

 unable to divide. They 

 grow to a large size, and 

 store up a considerable 

 amount of reserve -nutri- 

 ment in the cytoplasm. 

 These forms are the most 

 resistant to external in- 

 fluences, and can survive 



long hunger-periods, in a gregariniform, resting condition. 1 With 

 the advent of fresh blood into the stomach of the gnat, the female 

 forms undergo a process of parthenogenesis, consisting of nuclear 

 reduction and a kind of self-fertilisation. Thus rejuvenated, they 

 are able to give rise to a fresh succession of Trypanosomes of all 

 three types. 



The Behaviour and Development of the Trypanosomes in the Blood of 

 tJie Owl. All the Trypanosomes met with in the bird can be recog- 

 nised as belonging to one of the three categories observed in the 

 gnat. On entering the blood, the small indifferent forms at once 



1 According to Schaudinn, these gregariniform females can bring about hereditary 

 infection, remaining dormant in the ovaries until the eggs are laid and the larvae 

 develop. 



Development of a female Trypanosome from an 

 ookinete of female character. (After Schaudinn.) 

 m.n, degenerating male nuclei ; a.sp, tirst axial spindle 

 of female nucleus; f.t, female trophonucleus; /./,-, 

 female kinetonucleus. 



