lo Laidlaw, Classification of the Poly clad Turbellaria. 



(a) Prostatic duct and vesicular duct opening in- 

 dependently, body rather long. 



Idioplana ('97)' 



(/3) Prostatic duct and vesicular duct unite at base 

 of the penis, body round. Woodworthia} 



b. No nuchal tentacles or marginal eyes, body elongate. 

 I. No accessory vesicle. Penis with stylet. 



Stylochocestus^ 



c. No nuchal tentacles, body elongate, accessory part of the 



vagina opening to the exterior. Trigonoporui' 



C. Penis small, conical ; a pair of vesicul^ seminales 

 present. 



1. Body rounded, pharynx sub-central, no eye-spots. 



Acelis ('96) 



2. Body elongate, pharynx lying far back, eye-spots 



numerous. Latocestus ('96) 



II. Prostate lying about the course of the vesicular duct (ductus 

 ejaculatorius). 

 A. Tentacles or tentacle eye-groups present. Pharynx 

 sub-central, penis without a penis sheath, 

 a. Nuchal tentacles, no marginal eye-spots. Penis small 

 conical, with stylet. 



1. A common genital atrium. Stylochoplana. 



2. Gonopores separated. 



a. Prostate chambered. 



f Antrum masculinum very long. Pharynx 

 normal, accessory vesicle present. 



Notoplana (:03rt) 



ft Antrum masculinum not very long, pharynx 



transversely elongate, no accessory vesicle. 



Plagiotata ('96). 



/3 Prostate not chambered, no accessory vesicle. 



* Prostate very long, gonopores close together. 



Alloioplana ('96). 



** Prostate small, lying close about the base 



of the penis, antrum masculinum large 



and muscular. Hoploplana (:02). 



^ Woodworthia, a new genus closely allied to Idioplana, and Stylochocestus, 

 will be described in Prof. Herdman's forthcoming report on the Ceylon Pearl- 

 fisheries. 



" See note C. 



