174 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Fig. 34. Corkscrew-shaped copulatory organ of P. bifidus, 
(after v. Graff). 
Fig. 35. Cylindrostoma quadrioculatum, Leuckart. 
Fig. 36. Head of C. quadrioculatum, 
Fig. 37. Monotus fuscus, Cirsted. (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 tremellaris,O.F.M. From the living 
compressed animal, ventral surface. Natural 
length 18 mm. (X 2). 
Fig. 41. Cycloporus papillosus, Lang. (xX 8). 
Fig. 42. Oligocladus sanguinolentus, Lang. Length 11 
cm. (X4). 
Fig. 43. Stylostomum variabile, Lang. An immature 
specimen (X 5). ny 
Figs. 44—46. Diagrams to illustrate the relation positions 
of mouth and genital aperatures, and other 
points which distinguish the genera Cycloporus, 
Oligocladus and Stylostomum, (after Lang). 
