216 H. M. WOODCOCK. 



this structure. For it can scarcely be doubted tliat this 

 characteristic organella of Trypanosomes is homologous in 

 all cases, and agrees, in origin and significance, with the kineto- 

 nucleus of Trypanomorpha above described. Although, 

 unfortunately, very little is known in most cases about the 

 minute structure of this body, owing to its propensity for 

 staining up deeply, the evidence afforded by the work of 

 Schaudinn and Prowazek is, we think, sufficient to justify 

 this view. 



One or two additional confirmatory points may be men- 

 tioned. In the first place there is the well-developed nature 

 of the kinetonucleus in Trypanoplasma borreli, where 

 it may be almost as large as the trophonucleus, and the same 

 remark applies to the other species of this genus. ^ Again, in 

 the ookinetes of T. barbatulee (see below. Section IX), Leger 

 has observed heteropolic division of the single large nucleus, 

 doubtless leading to the formation of tropho- and kineto- 

 nucleus. Lastly, Bradford and Plimmer (6) have themselves 

 observed the latter body given off from the larger, trophic 

 nucleus (the '' macronucleus ^^ of these authors) in Trypano- 

 soma brucii. 



The kinetonucleus in an adult Trypanosome is always 

 situated normally in the non-flagellated half of the body. 

 Its distance from the end varies considerably, even in differ- 

 ent individuals of the same species. The more slender and 

 tapering tlie extremity, the fai-ther away from it, usually, is 

 the kinetonucleus. In certain forms, e. g. T. mega (fig. 58), 

 T. trausvaaliense (fig. 50c), and some individuals of T. 

 rotatoriuui (17 b, 5G a) and of T. inopinatum (17 c), it lies 

 more centrally, and is often contiguous to the trophonucleus. 

 The kinetonucleus is usually rounded in shape, but may 

 be sometimes elongated or rod-like, as in T. inopinatum, 

 T. johnstoni (fig. 51), T. trausvaaliense, and Try- 

 panoplasma borreli (fig. 18), with its axis either transverse 

 or longitudinal. It attains its largest size in certain Piscine 

 forms, e.g. T. solea); in these cases it frequently occupies 

 ' To judge, that is, from Plehn's rather unsatisfactory figures (84). 



