THE HAEMOFLAGELLATES 233 



presumably, T. grayi passes into the outer world, to be swallowed 

 subsequently by its alternate host. 1 



Comparing T. grayi with T. Irucii, an essential point of contrast 

 is at once noticed. In the first-named, the small, Herpetomonad 

 forms, which have the function of propagating the infection to a 

 fresh host, occur mainly in the proctodaeum and leave the fly per 

 <ui urn. In the latter, on the contrary, the small, Crithidial forms, 

 which are compared by Minchin with those of T. grayi just men- 

 tioned, were found almost exclusively in the proboscis ; moreover, 

 no Trypanosomes of any kind Avere seen in the hindermost part of 

 the gut (proctodaeum). Hence the propagation of T. Irucii would 

 appear to be just as certainly by the inoculative method as that of 

 T. f/rayi is by the contaminative one. Further, just as there is at 

 present no evidence of contaminative infection in T. brucii, so there 

 is none of inoculative infection in T. grayi ; for although Minchin 

 says that the slender type, which he also thinks is a propagative 

 form, was met with farther forward than the Herpetomonad type, 

 it was not met with farther forward than the stomach. And this 

 is as far as our knowledge goes up to the present. 



Schaudinn's Work on Haematozoa of the Little Owl. 



There remains for consideration the remarkable research of the 

 late Fritz Schaudinn on certain parasites of Athene nodua and Culex 

 pipiens, namely, I'rypanomorpha (Trypanosoma) noctuae and " Try- 

 panosoma " (Lemocytozoon, Spirochaeta) ziemanni. Exigencies of space 

 preclude a detailed account of this work, only the main outlines 

 of which can be given here, but a full description will be found in 

 the writer's article on the Haemoflagellates (3). 



Taking first Trypanomorplw, noctuae, the life -cycle may be con- 

 veniently commenced with the motile copula or ookinete resulting 

 from conjugation in the stomach of the gnat. While the nuclear 

 fusion of the two sets of elements (kinetic and trophic) derived 

 from the original gametes is being completed, leading to a single, 

 large, compound nucleus, the ookinete is getting rid of unnecessary 

 material, such as the pigment-grains and reduction-nuclei left over 

 in the cytoplasm (Fig. 10, A, B). Even in the ookinete stage, 

 Schaudinn recognises the three types of individual, indifferent, 

 male, and female, distinguishable by differences in the size of 

 the nuclei relative to the cytoplasm, and by the varying appear- 

 ance of the latter. 



The development of an indifferent Trypanosome has been de- 

 scribed above (p. 213). When formed, a period of active movement 

 and multiplication sets in, succeeded later by a resting condition. The 



1 The reasons for considering that this parasite is not merely a " fly-parasite " 

 have been given on p. 201. 



