248 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
The terminal buds of fishes have been often described and figured, and I have 
little to add to the classical descriptions save in the matter of distribution and inner- 
vation. Those in the mouth are supplied by branches of the x, ix, and vii pairs of 
cranial nerves, the first two nerves supplying those in the gill regions and the pre- 
trematic branch of the glossopharyngeus also running forward to supply those on 
the hyoid arch (tongue). The communis root of the facialis (=portio intermedia of 
human anatomy) and its geniculate ganglion supply the taste buds on the palate by 
the r. palatinus facialis (= great. superficial petrosal nerve of man), and other buds 
on the lining of the cheek, on the jaws, and on the lips by other branches, some of 
which are secondarily associated with branches of the trigeminus and most of which 
have no homologous in mammalian anatomy, though some one or more of them 
probably represent the chorda tympani. 
In Ameiurus I have shown (’01) that terminal buds occur in the skin of practically 
the whole body surface, most abundantly on 
the bardlets and diminishing in frequency 
toward the tail. These buds (see fig. 2) 
rest on a low papilla of the dermis, quite 
different from that figured by Merkel (’80, 
plate v, lig. 1) for the terminal buds of 
Silurus. Ilis figure shows a much smaller 
organ, resting upon a greatly elongated 
papilla in an epidermis which is apparently 
thicker than in Ameiurus. Merkel states 
(’SO, p. 72) that terminal buds always occur 
on such a dermal papilla. While this is cer- 
tainly the general rule, we find occasionally 
instances where the papilla is absent, as on 
the lilliform fins of the hake, where I find the 
buds imbedded in the epidermis and extend- 
ing only partway through it, with a layer of 
unmodified epidermal cells between the bud 
and the dermis. 
All parts of the body of Ameiurus which are supplied with terminal buds are 
reached by branches of the facial nerve from the geniculate ganglion. In other 
words, the rami from the communis root of the facialis are distributed to nearly the 
whole outer body surface of this fish. On the distal side of the ganglion these rami 
usually join themselves to other cutaneous branches which are phylogenetically older, 
belonging to the general cutaneous and lateral lino systems. Even the great recur- 
rent branch into the trunk, the ramus lateralis accessorius, which passes out of the 
cranium as a practically pure communis nerve, anastomoses with the spinal nerves at 
their ganglia and its fibers are ultimately distributed along with the general cutaneous 
fibers from these spinal ganglia. Fig. 3 illustrates the courses of the chief cutaneous 
branches of the communis system in Ameiurus meins , the nerves of all other systems 
being omitted from the. sketch. 
Proximally of the geniculate ganglion the communis root of the facialis pursues 
an uncomplicated course to the primary gustatory center within the medulla 
oblongata. In most fishes this root passes back close to the floor of the fourth ven- 
Fig. 2. — Section through the skin of the top of the head 
of Ameiurus mclas, showing a terminal bud. x 375. 
(From the Journal of Comparative Neurology, vol. xi, 
. No. 3, Oct., 1901, plate xvii, fig. 11.) At rl is the dermis, 
which is raised into a low papilla under the sense organ 
and whose center is pierced by the nerve for the organ . 
