409] AKOPLOCEPHALIDJE—DOUTHITT 59 



position and form of genital organs and excretory ducts, that it is the 

 most generalized, unless "Taenia" anoplocephaloides be given a lower 

 place. The following facts argue that Linstowia is descended from the 

 higher Anoplocephalinae, from forms somewhat like Schizotaenia and 

 its relative Moniezia. 



1. The uterus, in some Schizotaenia and Monieziae, in its fully 

 developed stage is divided up into compartments much like the embryo- 

 capsules of the Linstowinae. 



3. The uterus of the Linstowinae, in anlage, is not different in 

 type from the diffuse uterus of the genus Schizotaenia. 



3. The uterus apparently crosses the excretory ducts dorsally in 

 the Linstowinae; information is vague or wanting as to most species, 

 however. 



4. The genital ducts have been observed to cross the excretory 

 ducts ventrally in some individuals in Schizotaenia. 



5. The cirrus pouch is unusually large in Schizotaenia and Lin- 

 stowia. 



The following diagram represents the scheme of evolution here 

 proposed. 



AyvtelUna 



Thysanosoma 



\ntrtmcn)>iifer 

 ZschcWcttllal Thysanottnia 



StlUsia. \ \ | Triplatatnu 



? 

 Schizotaenia 



Btrtulla 

 5j)tciaUzed Andrw / / Aporinx 



Prinultvt Andryat\ 



Ancestral bnoflocephalui&e 



