24 8 THE HAEMOFLAGELLATES 



8. SYSTEMATIC. 



The reasons for the division of the Trypanosomes into two 

 distinct families have been alluded to in the previous section. 

 Besides the fundamental diagnostic characters, namely, the true 

 orientation of the body and the biological features associated there- 

 with, it is quite likely that important differences in regard to the 

 life-cycle will become evident as our knowledge increases. 



SUB-ORDER MONADINA. 



Family TRYPANOMORPHIDAE, Woodcock. Haemoflagellates 

 derived from a uniflagellate, Herpetomonadine form, in which the 

 point of insertion of the flagellum into the body has travelled back- 

 wards from the anterior end for a considerable distance, the 

 flagellum itself having become, concurrently, attached to the body 

 for part of its length by means of an undulating membrane. At 

 present only one genus is distinguished. 



Genus Trypanomorpha, Woodcock. With the characters of the 

 family. The genus was founded for Schaudinn's Avian parasite, 

 Trypanosoma (Halteridium) noctuae (Celli and San Felice), 1 from 

 Athene noctua and Culex pipiens. As above mentioned, it is probable 

 that other Avian forms, and perhaps some Mammalian ones, will be 

 found to agree with this generic type ; at present, however, it is 

 not possible to say which with any certainty, and hence they are 

 retained under the heading " Trypanosoma" 



Reference has been made to the possibility of Le"ger's Crithidia 

 fasciculata from Anopheles maculipennis, and other Insectan parasites 

 which show marked trypaniform characters, being also really 

 Haemoflagellates. In such a case the genus Trypanomorpha may 

 prove to be synonymous with Crithidia ; if so, the latter name will 

 take priority. Liihe, it is to be noted, in his account of the 

 Haematozoa (I.e.), regards all the Trypanosomes of Mammalia as 

 belonging to the Herpetomonadine type, and has proposed the new 

 generic name Trypanozoon for these forms. 



SUB-ORDER HETEROMASTIGINA. 



Family TRYPANOSOMATIDAE, Doflein. Flagellates, with but 

 few exceptions haemal parasites, derived from a bi flagellate, Bodo- 

 like type, in which the posteriorly directed (trailing) flagellum is 

 always present arid attached to the side of the body by an undu- 

 lating membrane, of which it constitutes the thickened border. 



1 Schaudinn placed this form in the genus Trypanosoma. We incline, however, 

 to the view that the type-species of that genus (T. rotatorium) is a Heteromastigine 

 type, and therefore restrict that genus to such forms. 



