Structare of an Aw^trdllan Lund Leech. 233 



EXPLANATION OF PLATES. 



Plates X.— XIV. 



Fig. L Diagrammatic plan of the amuili and segments of 

 Philcemon piingois. 



Fig. 2. Diagrammatic plan of the structure of Phiheiiwii 

 puiigens. The dotted outline represents the 

 alimentary canal. The female reproductive 

 organs are omitted. Two only of the nephridia 

 are represented. The nephridial pores are indi- 

 cated on the left side, the most anterior pore 

 lying in the sixth annulus. Neph. represents 

 the opening of the last nephridium. The pos- 

 terior organs are indicated with their ducts 

 opening into the last pair of diverticula of the 

 crop. 



Fig. 3. Dorsal view of Philceinon pnngens. x 3. 



Fig. 4. Dorsal view of the posterior extremity of the same. 

 X 6. An. Anus. Neph. 17, opening of pos- 

 terior nephridium. 



Fig. 5. Section through a segmental sense organ drawn under 

 Zeiss, F. oc. 2. Tlie four clear cells are shown. 

 In the upper left hand one the nucleus can be 

 seen. Ax. Axial fibres of the eye. n. Nerve. 



Fig. 6. Longitudinal section through an eye. Drawn under 

 Zeiss, C. oc. 2. The clear cells are seen lying in 

 the pigment cup. c.c. 1. The central projection 

 into the vacuole of the clear cell. Bv. Blood 

 vessel within the pigment cup. 



Fig. 7. Outline drawing of a longitudinal section through an 

 eye to show the division of the nerve supplying 

 the organ. 



Fig. 8. Section through one of the marginal lip organs. 

 Drawn under Zeiss, F. oc. 2. T. tactile cells. 

 C. cuticle. Bv. blood vessel. Nci. nuclei of 

 tactile cells. Tc. cut ends of tactile cells. C.C. 

 clear cells. N. nerve. 



