N. H. SWELLENGREBEL 
477 
It would take too long to compare in this paper all the stages of 
degeneration with Prowazek’s figures of nuclear reduction, gametogenesis, 
etc., but if the figures are compared, it will be seen that they are 
remarkably alike and that their resemblance cannot be explained as 
merely due to coincidence. 
(c) Changes of the shape of the cell. (Diagram XIV, fig. 13.) 
Little is to be said on this point. Cells as shown in fig. 13 were not 
commonly seen. Perhaps these forms are to be compared with Moore 
and Breinl’s “latent bodies,” but this cannot be affirmed with certainty. 
It might be argued that these degeneration forms and the stages of 
development found in the gut of Haematopinus are not to be compared, 
although bearing some superficial resemblance to each other. This, 
however, is not the case. As Strickland and I have shown and as may 
be seen also in Diagram XV, both the same phenomena, viz. hypertrophy 
Degenerating T. lewisi in the gut of Hsematopinus spinulosus. 
and fragmentation of the blepharoplast (figs. 1—3) and formation of 
chromidia and fragmentation of the nucleus (figs. 4, .5), are also to be 
found in trypanosomes in the gut of the rat-louse, if no further de¬ 
velopment takes place. 
4. Summary. 
The development of T. lewisi in the blood of the rat is accompanied 
by a division of the nucleus which is more like an amitosis than a 
mitosis. 
The division of the blepharoplast, always preceded by the division 
of a karyosome-like granule, might be called a promitosis (sensu: 
Nagler, 1909). 
It is not proved that autogamy or parthenogenesis takes place in 
rats’ blood or in cultures. The evidence brought forwai’d by Prowazek 
31—2 
