4:20 
R. T. YouDj 
concensus of opinion today is that this is the dominant, if not the ouly 
method of cell multiplication in these worms. Child himself, after a vain 
attempt to prove his point, admits (1911, p. 280) that ‘‘The whole problem 
of amitosis seems to me somewhat unprofitable at present as a subject 
for Investigation on a purely observational basis. Experiment is necessary 
before we can reach any certain conclusions as to the signifirance of either 
niitosis or amitosis in the life of the cell.” 
In my own studies upon a large nnmber of species I have frequently 
found mitoses present, and were it not for the impossibility of bringing 
the development of the gerni cells into line with the ordinary processes 
of gametogenesis in other animals, I should be wüling to admit that the 
whole contention for amitosis in cestodes rested upon a very insecm’e 
foundation. It is this impossibility however together with certain posi- 
tive observations, which still causes me to adhere to my former contention 
(Youxg 1913, p. 406) “that mitosis in cestodes is a degenerating process, 
probably in correlation with their otherwise degenerate character.” 
It is these observations, together with a review of previous work 
which I wish to present in the following paper. 
Acknowledgments. 
Most of the investigation upon which these observations are based 
has been done in my own laboratory in the University of North Dakota, 
but acknowledgments are due Professors E. B. IVilsox and IV. G. Mac 
Callum for permission to use their laboratories in Columbia University, 
and to Dr. F. R. Lillie for the prhülege of a room at the Marine Biological 
Laboratory, during a portion of the work. To all of these gentlemen my 
hearty thanks are due for the many comtesies accorded me. 
Material and Melhods. 
The material employed has come from many soiu-ces and includes a 
large number of species from several families and Orders. Taenia pisi- 
formis, the gametogenesis of which has aheady been described by me 
( Youxg 1. c.) and Rhyncobothrium bulbifer have been my chief sources 
of information, but my studies of these types have been extensively 
amplified by examination of other forms. The observations are based 
mainly on preserved material, corroborated however by considerable 
examination of Imng specimens. 
Many different methods of fixing and staining the preserved material 
have been employed, the best results in general being obtained with 
Flemmen'gs strong solution and iron haematoxylin stain. Living material 
