jMessrs. Hancock and Embleton on the Anatomy of Eolis. 185 



and seems to present a small ganglionic enlargement. We have 

 numbered them in the order in which they occur, commencing 

 at the median line in front. 



The first and second pairs, very minute, come out of the un- 

 der surface of the anterior commissure of the first or cerebral 

 ganglia, and pass to the skin on each side of the median line 

 before and behind the dorsal tentacles. 



The third pair, large nerves, come out of the first cerebral 

 ganglia at their upper surface, and near the middle of their an- 

 terior border ; they pass forwards, upwards and downwards to the 

 roots of the dorsal tentacles, within which each suddenly swells 

 out into a remarkable ganglion, e, of an irregularly oval form, 

 which, at its upper end, divides into three or four processes, each 

 giving ofi" nerves to be distributed for the supply of the whole 

 tentacle. This pair we look upon as the special nerves of smell- 

 ing, for reasons which will be adduced hereafter, and as endowing 

 the tentacle with the power of ordinary sensation likewise. If 

 this view be correct, then the small branches passing from the 

 ganglion to the sentient surface of the tentacles are properly to 

 be designated olfactory nerves, and the thick pedicle supporting 

 the ganglion and connecting it with the cerebral ganglion, olfac- 

 tory tractus. 



The fourth and fifth pairs, considerably less than the third, 

 arise also from the anterior part but under surface of the same 

 ganglia, close together, and just outside of the third. The fourth 

 runs forward to the outer lip before giving ofi^ any branches ; 

 after that it divides and subdivides minutely, and goes to supply 

 the outer lip above and below. The fifth runs forward and is 

 distributed to the skin of the head and between the dorsal ten- 

 tacles, but does not give ofi" such numerous branches as the pre- 

 ceding nerve. 



The sixth, one of the largest nerves in the body, comes out of 

 the external anterior angle of the ganglion, and after a short 

 course outwards and forwards bifurcates. The two branches are 

 about equal in size : one passes into the oral tentacle, divides into 

 two branches which subdivide and supply the tentacle ; the other 

 runs forward, and then inclines inwards towards the median 

 line, and subdivides into many twigs which are distributed upon 

 the roof of the channel of the mouth. 



The seventh and eighth are minute nerves which issue from 

 the outer margin of the ganglion just behind the sixth. They 

 take a straight course outward and pass into the skin of the side 

 of the head. 



The ninth is a large pair, coming out of the same ganglion 

 just behind the preceding, and running outwards and forwards 

 gives off" a twig which goes to the muscles attaching the buccal 



