670 H. M. WOODCOCK. 



thirds or more of the length of the body, while in others they 

 occupy only the middle portion (fig. 35). Now and again 

 these bands appear very narrow, but in no case can they be 

 considered as lines or striations ; T do not think they have 

 any connection with, or themselves indicate, actual myo- 

 nemes. Button and Todd (4) have described what is pro- 

 bably a similar cytoplasmic differentiation in Trypano- 

 soma mega and T. karyozeukton. They distinguish 

 the loose, spongy aflagellar region as ''spongioplasm," and 

 the region of the longitudinal bands as " hyaloplasm." The 

 chief difference in their cases is that the dark bands are 

 very broad and very compact, showing less obviously their 

 granular structure, while the alternating, less granular zones 

 are very narrow and pale, and appear as clear stripes. 



I liave never seen any indications of division in any 

 parasites belonging to either of the above types. 



The next series of forms of Trypanosoma fringilli- 

 narum to be described consists, on the Avhole, of small 

 parasites, some of which are extremely small. These forms 

 have been found in two cases. The first instance of their 

 occurrence noted was in the bone-marrow of a naturally 

 infected chaffinch, which was killed about the middle of 

 March. This bird had the usual scanty number of ordinary 

 definitive trypanosomes in the general cii-culation, and these 

 are also present in the bone-marrow, along with the para- 

 sites of small type. The other case was in the chaffinch 

 which was found to have a mixed infection of Halteridia as 

 well as trypanosomes towards the end of June (cf. p. 660). 

 In this bird the trypanosomes were comparatively numerous 

 in the blood ; but no individuals of the ordinary large type 

 have been found in any of the preparations, whether from 

 the blood or organs. As I shall frequently have to dis- 

 tinguish between these two cases, it will be convenient, and 

 will, I hope, render the description clearer, to refer to them 

 as case A (the former, earlier case), and case B (the second, 

 later case), respectively. 



T will begin the account of this small type of form by 



