48 THE ZOOLOGIST. 



(3) Usually unarmed. 



(4) A single, or, rarely, a double set of reproductive organs 



in each segment. 



(5) Genital pores marginal and bilateral, unilateral, or regu- 



larly or irregularly alternate. 



Subfamily Diphyllin^. 



(1) Rostellum armed or rarely absent. 



(2) Suckers unarmed. 



(3) A single set, or, rarely, a double set of reproductive 



organs in each segment. 



(4) Uterus sac-like, simple or lobulated, or not persistent, 



breaking down into numerous egg-capsules, each con- 

 taining one or several eggs. 



(5) Pora-uterine organs not developed, adults in birds, 



mammals, and reptiles. 



The diagnostic character of each genus will now be given 

 also : — 



Genus Dilepis (Weinland, 1858). 

 (From Cestodes of North American birds, by Eansom.) 



Generic Diagnosis. 



(1) The rostellum armed with a double crown of hooks, which 



possess long dorsal but short vertical root and a long 

 blade. 



(2) The inner longitudinal muscle layer consists of numerous 



bundles. 



(3) Genital pores unilateral. 



(4) Genital canals pass dorsal of the longitudinal excretory 



vessels and nerves. 



(5) Vas deferens coiled. 



(6) Seminal vesicae not developed. 



(7) Testicles in medullary portion of segment surrounding 



the female glands at the sides and behind, typically 

 numerous (40-50), but may be reduced in number 

 to 7. 



(8) Uterus sac-like, with few or numerous out-pocketings. 

 Adults in birds and animals. 



