184 RALPH EDWARD SHELDON 
Innervation. From the olfactory cells arises the unmedullated 
fibers which, passing through the lamellae, form the olfactory 
nerve. Medullated fibers penetrate the central ridge, ending 
immediately underneath the epithelium (fig. 5). Such an inner- 
vation has been described in no other anamniote (Sheldon, 
’08 b), although it has long been known that in mammals, partic- 
ularly in man, such fibers take part in the innervation of the 
nasal mucous membrane. 
In 1903 Rubasehkin demonstrated their presence in birds. 
Practically all Amphibia and many fishes have been studied with 
reference to this point, but in no case have medullated fibers been 
demonstrated beyond doubt, although Aichel in 1895 believed that 
he found something of the kind in embryo teleosts. In six Wei- 
gert series through the olfactory capsules, bulbs and crura of the 
adult carp it has been possible to demonstrate the presence of 
medullated fibers in the tunica propria of the Schneiderian mem- 
brane, part of which evidently distribute to the epithelium, as 
they can be traced to the membrana propria itself. These latter 
probably end in free nerve terminations, as there are no special 
organs developed. Part of the fibers entering the tunica pro- 
pria join the bundles of unmedullated fibers and apparently run 
to the mucous membrane of the lamellae with them. The re- 
mainder of the medullated fibers innervate the skin about the 
nasal capsule. 
All of these medullated fibers are derived from the supra- 
orbital trunk, which is made up of general cutaneous fibers from 
the Gasserian ganglion (nervus ophthalmicus superficialis tri- 
gemini) and sensory fibers from the facial (nervus ophthalmicus 
superficialis facialis). This latter nerve is composed partly of 
fibers from the dorsal lateralis ganglion, and partly of visceral 
sensory fibers from the geniculate ganglion. The fibers entering 
the tunica propria are certainly not acustico-lateral, since no canal 
or pit organs are developed in connection with the epithelium; 
the fibers are also smaller than are the lateralis fibers. They 
may, therefore, be either general cutaneous or visceral sensory, 
with the preponderance of evidence in favor of the former. This is 
due, in part, to the fact that in birds and mammals such innerva- 
