80 ILLINOIS BIOLOGICAL MONOGRAPHS [430 



the genera Moniezia and Schizotaenia constitute the highest types of the 

 Anoplocephalinae ; the other subfamilies of the family seem to have 

 sprung from forms like these two genera. 



6. Cestodes exhibit a high range of variability which should be 

 taken strictly into account in morphological, phylogenetic, and syste- 

 matic studies. Generalizations not founded upon plenty of material and 

 careful study and reflection do more harm than good. The following 

 reference list of variations and anomalies reported in this paper shows 

 the need of extreme caution in coming to conclusions regarding struc- 

 ture and consequent relationships. 



Andrya communis — relation of cirrus pouch to excretory 



ducts page 9 



translucida — genital functions page 14 



excretory ducts page 15 



Anoplocephala variabilis — variations due to state of contraction, .page 23 



variations due to habitat page 24 



Schizotaenia variabilis — size and distribution of testes page 33 



excretory system page 34 



anoplocephaloides — course of genital ducts page 36 



position of cirrus pouch page 36 



distribution of testes page 37 



form of ovary page 38 



excretory ducts page 39 



Cittotaenia pectinata — distribution of testes page 46 



number of proglottids page 46 



perplexa — distribution of testes __ page 47 



size and shape of cirrus pouch page 47 



perplexa and pectinata compared page 48 



