ELEDONE. 537 
smaller oval ganglion (fig. 71, 0.g.). | Chéron termed 
this the olfactory ganglion, but Zernoff denies its 
connection with the olfactory organ. 
A. (2) The Olfactory nerves.—The strands of the 
olfactory nerve are, at their origin, indistinguishable from 
those of the optic nerve. They lie’ ventral to these, 
however, and run along with them to the optic ganglion. 
Here they separate, and run on as a separate nerve, which 
is absolutely independent of and unconnected with 
Chéron’s olfactory ganglion (fig. 71, olf. N.). Beyond 
the separation from the optic nerve it may be seen, 
running external to the white body, on the internal wall 
of the orbit (fig. 71, «.), where it pierces the wall of 
the eyeball and then runs over the dorsal posterior wall 
of the eye to the olfactory pit, which it innervates 
foie te. (4, olf. NV. and olf. P.). 
A. (3) Labial nerves.—These are four pairs of fine 
nerves, which run out from the anterior edge of the 
cerebral ganglion and innervate the lip (fig. 76, a, 4, «, 
and d). Leaving the cranial cavity, they pierce the 
membranous wall which closes this cavity anteriorly, and 
then run over the outer wall of the sinus venosus, which 
here surrounds the buccal mass, anterior salivary glands, 
and oesophagus (fig. 76, S. V.). Anterior to the sinus 
venosus, they run over the outer wall of the huccal mass, 
and so finally reach the lip, where they end in fine 
branches. The innermost pair of labial nerves (fig. 76, a) 
leave the cerebral ganglion one on each side of the 
middle line, and running along the outer wall of the 
sinus venosus, each soon divides into two branches. 
Reaching the anterior limit of the sinus venosus, each 
half again gives off several small branches, which end 
finally in the lip. ‘The second and third pairs have a 
similar course, the third pair being rather stouter than 
