682 II. M. WOODCOCK. 



latter case, and I have uo reason whatever to think that one 

 set of cultural forms shows any intrinsic differences from the 

 other, which would imply that the trypanosomes from the 

 chaffinch and the redpoll, respectively, are distinct parasites. 



The predominating type of the trypanosome in the cul- 

 tures is a well-defined and characteristic form, which may be 

 termed the trypanomonad form of the parasite, deriving 

 this convenient general designation from one of the various 

 alternative (synonymous) names (viz. Trypanomonas) 

 given by Danilewsky to certain parasites described by him. 

 This type is elongated and slender, the width usually varying 

 but slightly in the middle of the body, and diminishing more 

 or less gradually towards the atlagellar end. The essential 

 diagnostic characters are : (1) The two nuclei are always 

 close together, and situated eioher about the middle of the 

 body, or else distinctly in the aflagellar half ; and (2) the 

 fiagellum is attached for some distance to the side of the 

 body, forming a distinct undulating membrane. The mem- 

 brane may be at times fairly prominent, and possess a wavy 

 edge, indicating a slight development of pleats or folds. 

 The kinetonucleus is never near either end of the body. It is 

 important to note that the flagellar end of the body is drawn 

 out with the flagellum, as it were, and ultimately thins away, 

 leaving the tlagelluni free. This condition is of very general 

 occurrence, of course, among trypanosomes (as seen in the 

 blood), and is the natural consequence of the presence of an 

 undulating membrane. In respect of all the above features, 

 therefore, the trypanomonad type differs essentially from a 

 herpetomonad form. 



Typical examples of the trypanomonad form, showing para- 

 sites of medium to large size, are seen in figs. 7, 8, 71-75, and 

 figs. 13, 77-79, from preparations of cultures from the chaf- 

 finch and redpoll respectively. To give an idea of the size 

 of these forms, three principal measurements may be taken : 

 (a) length of body alone, (b) greatest width of body, and 

 (c) length of free fiagellum. These dimensions, in the case 

 of some typical individuals, are as follows (in^) ; fig. 72 — (a) 



