Ph-4-=N-A,5 



Fig. 8. Chief forms of Polycladida : A-C, Acotylea ; D-F, Cotylea. A, Planocera 

 graffii Lang, nat. size ; B, Stylochoplana maculata Stimps, x 7 ; C, Cestoplana 

 rubrocincta Lang, x |; D, Anonymus virilis Lang, x 3, ventral surface ; E, 

 Thysanozoon brocchii Grube, nat. size ; the head is thrown back and the pharynx 

 (ph) is protruded. F, Prosthiostomum siplmnculus Lang, x 3. Br, Brain ; CG, 

 cerebral eye group ; DM, true mouth ; Ey, marginal eyes ; m, mouth ; MO, 

 main-gut or stomach ; P, dorsal papillae ; Ph, pharynx ; s, sucker (ventral) ; 

 T, tentacles ; UP, dorsal median gut-branch. $, male, and ?, female, genital 

 aperture, except in D, where <$ refers to the multiple penes. (After Lang and 

 Schmidt. ) 



