THE H^MOi^LAGBLLATES. 321. 



(" SpirocliEeta ") type of form again. Various enigmatical, 

 rounded, and kidney-sliaped bodies were observed, which 

 might possibly belong to the life-cycle, but as no intermediate 

 stages were seen, this remains uncertain. 



Brief comment may be made upon one or two points in the above descrip- 

 tion. Tlie structure regarded by Krzysztalowicz and Siedlecki as a nucleus 

 cannot be said to resemble greatly that of a Trypanosome. In the trypani- 

 form parasites, at all events, it rather recalls tlie cytoplasmic vacuole of a 

 IVypanosome, both by its appearance and its relation to the kinetonuclear 

 grain. 



Moreover, in one long irregular parasite figured (probably an abnormal " com- 

 pound spiral") some of the "nuclei" certainly liave a distinctly vacuolar 

 appearance. However, Krzysztalowicz and yiedlecki think that in certain 

 dividing forms, where the " nucleus " is not apparent as a vacuole, it is repre- 

 sented by a deeper-staining region of the body, its enhanced chromaticity at 

 this time being due to nuclear changes. The solution of this point must 

 await further research. 



Again, with regard to the occurrence of a flagellum, Krzysztalowicz and 

 Siedlecki do not think that the spiroclisetiform parasites have one. Schaudinn, 

 on the other liand, thinks there is one at each end of the body. In some of 

 the former authors' figures of retracted and trypauiform individuals, the 

 appearance of the body at one end strongly suggests the presence of a 

 flagellum (cf. fig. 65 e) ; and this, moreover, at the end towards which the 

 sinuous, deeply-staining line runs, which is homologized with a flagellar 

 border, and which may very likely be continued (in some phases, at any rate) 

 as a free flagellum. It is more diflicult to judge in the case of the "Spirilla." 

 In one or two very spirilliform Trypanosomes (e. g. T. ziemanni, T. John- 

 ston i) the free flagellum is very short or absent. Supposing, however, there is 

 a flagellum at one end, it is hardly likely (if Spironema is a Trypanosome) 

 that there is also one at the other ; as a matter of fact, in certain indubitable 

 Trypanosomes, the non-flagellate end of the body is often almost, if not quite, 

 as fine as the flagellum itself (cf. T. ziemanni, Hanua's Trypanosome of 

 Indian pigeons [fig. 5S], and also T. poly plectrum). 



However this may be, there can be little doubt, from the 

 above account, that Spironema pallidum is allied, not to 

 the Spirocheetie, but rather to the Flagellates, possessing, 

 as it does, in certain phases at least, markedly trypauiform 

 characters. It is clear, moreover, that the parasites hitherto 

 grouped together under the general- heading of "Spiro- 

 chsetge" include, really, two quite distinct types of organism. 



