332 Mr. K. R. Lewin. The Behaviour of the [Sept. 15, 





Short and stumpy. 



Intermediate. 



Long and slender. 



Trypanosoma ganibieme . 



per cent. 

 51 2 

 32 -8 



per cent. 

 23 -1 



25 5 



per cent. 

 25 -7 

 41 -1 





This shows the percentage of the intermediate to be much the same in the 

 two species, whereas Trypanosoma gambiense is richer in short forms and 

 poorer in long than Trypanosoma brucei. 



Whether these slight differences are fundamental or only accidental it is 

 impossible at present to say, but enough has been written to show that 

 Trypanosoma gambiense and Trypanosoma brucei approach each other very 

 closely in size and shape. 



The Behaviour of the Infusorian Micronucleus in Regeneration. 

 By Kenneth E. Lewin, B.A., Senior Scholar and Coutts Trotter 

 Student of Trinity College, Cambridge. 



(Communicated by Prof. J. S. Gardiner, F.R.S. Received September 15, — Read 

 November 2, 1911.) 



The older experimenters on Infusoria have left very few records of the 

 behaviour of the micronucleus in regeneration. 



Balbiani ('91), in discussing the subject, declares that the presence of a 

 micronucleus is not essential to regeneration, since he had examined certain 

 regenerated merozoa* of Frontonia, Prorodon, Trachelitis, and Stentor without 

 finding a micronucleus even with the aid of reagents. He also cut conjugating 

 couples of Stentor at a time when the old meganucleus had started to 

 degenerate, and found that, unless a new meganucleus were formed, none of 

 the merozoa could regenerate. He concluded that the micronucleus has no 

 influence on regeneration. 



Stevens ('03) performed some experiments on Licnophora, and found that 

 regeneration occurred only in the micronucleate piece ; but as no regenera- 

 tion took place if more than three-quarters of the oral disc were removed, in 



* The word " merozoite " being well established in Sporozoan literature, I propose to 

 use the term " merozoon " suggested by Johnson ('93) for a cut fragment of an 

 Infusorian. 



