412 . Q. CLIFFORD DOBELL. 
ordinary forms in a most striking manner. They are usually 
of larger size (40-50) and possess a much modified nucleus 
(text-fig. A, 2). Although this modification varies—both as 
regards its type and extent—in different individuals, itisnever- 
theless always characterised by two features—enlargement 
and peripheral thickening (c f. text-fig. A, 2). Very often, the 
edge of the nucleus is thrown into folds (text-figs. B, C, 1). 
As will readily be seen from the figures, these moditied 
TrxT-FIG. A. 
Entameba ranarum. Drawings (to scale) showing the struc- 
ture of the nucleus (N) in an ordinary individual (1) and in one 
undergoing degeneration (2),in optical section. (The structure 
of the cytoplasm is not shown.) 
forms are very striking. For some time I was unable to 
determine their origin, and their proper place in the life-cycle 
of the amoeba; but I have now been able to prove that these 
unusual forms are undergoing a process of degeneration, 
which finally results in death. At first I obtained various 
isolated stages in the process in animals from different hosts, 
at different times, but I have now succeeded in following out 
