^916] Sicczy: Kiiiffointcli )is of FlageUntcs 233 



"idio-geiierative" chromatin and l)oth arising by an unequal division 

 of the original nucleus. 



With the refutation of tliese points the only reason that might be 

 advanced for retaining this classification would be the permanency 

 of the parabasal body as a cell organ and its specificity for these 

 forms. Among the Trypanoplasmidae and the Trypanosomidae, the 

 parabasal body has been figured, by almost every investigator in this 

 field within recent years, as a permanent cell organ, present through- 

 out all the known stages of the life-cycle. The earlier observations 

 have too much of doubt attached to them to withstand later results. 

 On the other hand, among the Haemosporidia included in the order 

 Binueleata no single undoubted instance can be found which shows a 

 structure comparable in its permanency and function to the parabasal 

 body of the trypanosomes. The granules which occur occasionally in 

 these organisms, and which have been claimed as the homologue of 

 the parabasal bodj', have no resemblance, either in morphology or in 

 function, to that organelle in the flagellates, and require a far-fetched 

 interpretation so to designate them. 



As has already been indicated, the life-cycle of the Haemosporidia 

 widens instead of bridges the gap between them and the flagellates, 

 and also indicates their relations to the Coccidia. On the other 

 hand, going outside the order Binueleata, other flagellates are found 

 which possess structures identical morphologically and functionally 

 with that found among the Haemoflagellata about which Hartmann 

 built up his order. These occur in at least three distinct orders, the 

 Protomonadina, the Polymastigina and the Trichonymphida. These 

 groups comprise the great majority of the parasitic flagellates, and 

 the occurrence of an accessory motor structure in them is significant 

 when the probable origin and function of that structure is in ques- 

 tion. Its formation in three distinct orders by a process of parallel 

 evolution, correlated with an endoparasitic mode of life, reduces the 

 value of the claims made for it as a basis of classification. 



Prom a consideration of these facts there seems to be no good 

 reason for retaining the Binueleata as an order of the Mastigophora 

 (Kofoid, 1916), and for uniting the Haemoflagellata with the Haemo- 

 sporidia. Far simpler is it to consider Trypanosoma, Trypanoplasma. 

 Leishmania, and Prowazekia as part of the order Protomonadina, and 

 the Haemosporidia in their present position in the Sporozoa. A more 

 natural system of classification can be attempted only with fuller 

 knowledge of developmental data than is now available. 



