I3O A. RICHARDS. 



is struck with the fact that according to the classification usually 

 given only members of one family, the Taenidae, are included in it. 

 This, of course, may be the merest coincidence owing, perhaps, 

 to the fact that members of the Taenidse are very readily secured. 

 The warning uttered by Young with regard to applying con- 

 clusions drawn from cestode observations to other groups, is, 

 however, more strongly emphasized. Not only are the results 

 which he had in mind deduced from a single class of animals 

 which are degenerate in a high degree, but they are drawn from 

 a single family of that degenerate class. 



MATERIAL AND METHODS. 



At the suggestion of Professor E. G. Conklin, the genus Tcenia, 

 upon which I had begun investigation with a view to obtaining 

 further evidence as to the occurrence of amitosis in cestode 

 tissues, was dropped for the present as a subject for research in 

 favor of Moniezia. The results which have been obtained upon 

 this latter genus by Child are of such unusual nature compared 

 with those of other forms that a reexamination would seem 

 desirable. In the light of my investigations upon Moniezia and 

 of Child's recent criticism I have again gone over my old material 

 of Tcenia as well as some newly prepared. 



In making these studies I am indebted to Professor E. G. 

 Conklin and to Professor Ulric Dahlgren for much kindly assist- 

 ance. My thanks are due to the management of the Wistar 

 Institute of Anatomy for assistance in obtaining material. Not 

 only were the facilities of the laboratory extended me for making 

 collections but my first lot of material was obtained and fixed 

 by Dr. Helen Dean King. To Dr. King I also owe thanks for a 

 number of technical suggestions. Professor C. M. Child, of the 

 University of Chicago, has also kindly placed facilities at my 

 disposal for obtaining specimens. 



Specimens of Moniezia expansa and of M. planissima have 

 been secured and fixed in a variety of fixing fluids: Flemming, 

 Hermann, Graf's chrom-oxalic, saturated aqueous solution of 

 corrosive sublimate, formol-sublimate, 1 Kleinberg's picro-sul- 



1 Physiological salt solution saturated with corrosive sublimate to which a few 

 drops of neutral formol are added. 



