Manchester Memoirs^ Vol. xlviii. (1903), No. 4- 9 



II. Diagnostic Table. 



ACOTYLEA. 



No sucker immediately behind the female gonopore. 

 Tentacles or tentacle eye-groups, if present, never mar- 

 ginal. Pharynx usually sub-central. Vagina often 

 provided with an accessory vesicle. 



I. Prostate separated from the ductus ejaculatorius and provided 

 with a duct of its own. 



A. Penis large, tubular, eversible ; its lumen lined with 



chitinous spines. With the prostate and usually 

 the vesicula seminalis it lies in an outer muscular 

 sheath. No marginal eyes. 



a. Nuchal tentacles present, body rounded, gut-branches 



few. 



1. Vesicula seminahs single, lying within the outer 



sheath. Lower part of the vagina with thick 

 muscular walls forming a bursa copulatrix. 



Planocera (:02)^ 



2. A pair of vesiculae seminales, lying outside the outer 



sheath. Lower part of the vagina with a 

 muscular, forwardly directed diverticulum. 



Paraplaiiflcerc^ (-03) 



b. Body elongate, no nuchal tentacles. 



I. Vesicula seminalis single, within the outer sheath, no 

 bursa copulatrix. Disparoplana^ i'-OZb) 



B. Penis small conical, prostate large, its duct short, vesicula 



seminalis single. 

 a. Nuchal tentacles and marginal eyes present. Body 

 rounded or rather elongate. (Penis without stylet?)^ 



1. Vagina without accessory vesicle, sexual openings 



near to each other and to the end of the body. 



Sfy/ocAus. 



2. Vagina and its accessory par;:s of great length. 



Where no reference is given to a genus it will be found fully described 

 in Lang's Monograph {'84). 

 See note A. 

 See note B. 



