698 H. M. WOODCOCK. 



older two (in the upper right-hand part of the figure), are 

 partially conHiient. 



It is important to note that agglomerations are formed 

 of individuals which are of a quite normal type. Nearly 

 all the parasites of the clusters figured, for example, are 

 definitely trypanomonad in character, either fairly long mid 

 fusiform, or belonging to the pyriform variety of individual. 

 Agglomerations of less typical forms, pseudo-lierpetomonad 

 in character, also occur, but I have not met with them to any 

 extent, even in old cultures. 



Novy and McNeal, in their account of cultures of avian 

 trypanosomes (14), make a great point of distinguishing 

 between multiplication rosettes and true agglomeration clus- 

 ters. They regard all rosettes in which the parasites are 

 joined by their flagella, corresponding, that is, to those I 

 have just described, as arising by successive multiplication 

 from a single individual, which starts the culture. Only 

 those cases, on the other hand, where the parasites are 

 united by their aflagellar ends, are considered to be true 

 agglomeration clusters. Until I myself came to work with 

 cultures, I had no idea but that the view of these authors was 

 correct, and that these two opposite kinds of clusters resulted 

 from quite different processes. Studying Novy and McNeal's 

 description and figures in the light of my own work, I feel 

 sure that these authors have given an entirely wrong 

 interpretation of the clusters, which they regard as multi- 

 plication rosettes. Novy and McNeal consider that the whole 

 process starts from a single cell, which is more or less 

 rounded ofp, and has no flagellum. This gives rise, by division, 

 to a few cells, which now possess flagella; by further multi- 

 plication, a typical rosette of spindle-like forms is pro- 

 duced. 



Novy and McNeal's figures on Plates 8 and 9, which 

 are from excellent micro-photogi-aphs, are most instructive, 

 and are, in my opinion, convincing evidence that the view 

 these authors put forward is incorrect. Most of the figures 

 represent simply clusters, large or small, of different forms 



