62 BRISTOL. [Vol. XV. 



14. Some of these cells supply the fibers which Retzius and 

 Biedermann describe as ending in the ganglion. 



15. These rings are connected longitudinally by other bi- 

 polar cells which thus form direct axial paths for nervous 

 impulses in addition to those furnished by the central system. 



16. The relation of these rings to the distribution of nerves 

 in a body metamere affords striking proof in favor of Whitman's 

 theory of the formation of a metamere with five annuli from 

 one of three annuli, that is, the posterior half of annulus 2 

 in Clepsine becomes annulus 3 in Nephelis ; the anterior half 

 of annulus 3 in Clepsine becomes annulus 4 in Nephelis, while 

 the posterior half becomes annulus 5. 



17. There is some evidence that this peripheral system of 

 nerves is an old and very stable structure, and will be found in 

 the other leeches. There is already some evidence that it or 

 its forerunner is present in other annelids. 



18. The "giant" nerve cells in the two systems, central 

 and peripheral, are in close relation to each other, and are 

 strikingly alike in cytological characters. 



19. The sympathetic nervous system is well developed, and 

 is connected with the central nervous system at the "collar." 



20. The branches at this connection form a nerve circle in 

 front of the "collar," such as is found in the arthropoda. 



21.. The nerve cells in the sympathetic system are multipolar, 

 the processes forming meshes over the wall of the alimentary 

 tract. 



22. There is some evidence that the sympathetic system 

 persists in the post-anal region, extending in the axial line to 

 the muscles of the concave side of the sucker. 



