OLFACTORY CENTERS IN TELEOSTS 185 
tion is trigeminal and partly because the weight of evidence in the 
teleosts is against the supposition that visceral sensory fibers 
are present in this region. Part of the branch entering the tunica 
propria goes to the skin, as already noted; the number of general 
cutaneous fibers in the supra-orbital trunk is much greater than 
the number of visceral sensory. If there are visceral sensory 
fibers going to the mucous membrane, they must be unspecialized, 
as there are.no taste buds present; there is not the slightest evi- 
dence, however, that such fibers are here present. In their course 
from the supra-orbital trunk to the tunica propria the.medullated 
fibers pass partly between the two bundles of the olfactory nerve 
and partly directly laterad into the median ridge. 
Young gold fish and cod were studied with reference to the 
presence of medullated fibers in the mucous membrane, but none 
could be demonstrated. This may have been due, particularly, in 
the case of the gold fish, to the fact that the individuals were 
immature, as such fibers could not be found in young carp. 
As the main current of water would be forced along the ridge 
thus innervated by general cutaneous fibers, it is probable that 
their function is that of tactile response for solid substances in the 
water or else with respect to the strength of the water current 
or both (see also Kappers, with respect to the ‘Oralsinn,’ and 
Sheldon, ’09 b, on ‘Chemical Sense’). 
b. The olfactory nerve 
The olfactory fibers gather from the different lamellae in two 
main bundles. In general, the medial bundle is derived from 
the more rostral lamellae, while the lateral is derived from the 
more caudal. The fibers of the two bundles distribute to all 
parts of the rostral and lateral surfaces of each bulb, the lateral 
bundle causing a protuberance on the dorso-lateral surface of each 
bulb as shown in figs. 1, 6 (a). There is a quite general crossing 
of the fibers of the two bundles before they reach the bulb so that 
fibers from each reach all parts of the bulb (fig. 123). Apparently, 
however, the lateral bundle is more especially associated with the 
tractus olfactorius lateralis and to a somewhat less extent with the 
