THE H^MOFLAGELLATES. 205 



or even thinner than T. lewisi; T. gvanulosum (fig. 17 k), 

 for instance, is extremely woi*m-like. In Piscine forms 

 owing, probably, to their great length, the body is frequently 

 coiled or rolled up on itself, as in T. solese (fig. 17 j), and T. 

 raj £6 (fig. 62 b). Trypanoplasma, as exemplified by T. 

 borreli (fig. 17 p, g), differs from the majority of Piscine Try- 

 panosomes in being short and relatively broad ; the length 

 (of the body alone) is 20 — 22 ju, and the width 'Sh — 4i /x. 



Coming to the Amphibian pai'asites, T. inopinatum (fig. 

 17 c) somewhat resembles a Mammalian Trypanosome, and 

 T. nelspruitense (17 e) a Piscine form ; finally, there is the 

 well-known T. rotatorium, which, when most Trypanosome- 

 like, has the form of a thick spindle (17 b). Frequently, 

 however, this parasite is greatly flattened out, and, conse- 

 quently, very broad and stumpy (figs. 17 a and 56). A 

 similar polymorphism of form is described by Leger (64) in 

 Trypanoplasma borreli. Certain individuals are more 

 massive than others, and often, indeed, very short and 

 squat (fig. 18 b). 



There can be no doubt that, in some cases at any rate, this 

 variation indicates a difference in sexuality. We have already 

 seen that this is so in Trypanomorpha; and Leger inter- 

 prets, in the same manner, the broad distinctions between 

 different individuals of Trypanoplasma just mentioned (see 

 also below, in Section IX b). 



It is particularly necessary to bear this factor in mind in 

 considering the Avian Trypauosomes. For it is here, perhaps, 

 that we find the extreme types of form; and we are, unfortu- 

 nately, at present largely in the dark as to how far these 

 represent different parasites and how far polymorphism. 

 That one and the same species may appear entirely different 

 in different phases of the life-history is manifest on com- 

 paring the chief ''forms" of Trypanosoma ziemanni 

 described by Schaudinn. The asexual or indifferent type is 

 extremely thread-like (fig. 16 h), and, indeed, greatly resem- 

 bles a Spirochfeta. On the other hand both male and 

 female individuals (the latter especially) have the form of a 



