80 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Fig. 34. Corkscrew-shaped copulatory organ of P. hifidus, 

 (after v. Graff). 



Fig. 35. Gylindro stoma quadriomdatum, Leuckart. 



Fig. 36. Head of G. quadrioculatum, 



Fig. 37. Monotus fuscus, (Ersted. (The figure also re- 

 presents M. lineatus.) From the living animal. 



Fig. 38. Copulatory organ of M. fuscus. 



Fig. 39. Copulatory organ of M. lineatus. 



Fig. 40. Leptoplana tremellariSjO.^.M. From the living 

 compressed animal, ventral surface. Natural 

 length 18 mm. (X 2). 



Fig. 41. Gijcloporus papillosus, Lang. (X 8), 



Fig. 42. Oligocladus sangulnolentus, Lang. Length I'l 

 cm. (X4). 



Fig. 43. Stijlostomum variahile, Lang. An immature 

 specimen (X 5). 



Figs. 44 — 46. Diagrams to illustrate the relation positions 

 of mouth and genital aperatures, and other 

 points which distinguish the genera Gijcloporus, 

 Oligocladus and Stylostomum, (after Lang). 



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