56 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
l 
where it bifurcates. Each branch gives off a small twig-(Plate 2, 7 
fig. 4, na. l.4and na. l.”), which passes out through this gland to the skin, _ 
The more lateral of the two bundles again divides, and these three 
terminal divisions of the ramus (Plate 4, fig. 9) then emerge from the 
anterior side of the gland to innervate the skin overlying that region. 
The two small twigs proximal to the three terminal divisions (Fig. 4) 
supply a somatic sensory innervation to the olfactory epithelium. 
(b) Ramus medialis nasi. After giving off a few fibers to the 
olfactory epithelium, the median ramus supplies a larger branch 
(na. m.') to the skin over the nasal bone; the foramen (for. na. m.) 
through which this nerve emerges is clearly indicated in fig. 1, Plate 1. 
The main ramus then passes cephalad without branching to the 
extreme tip of the snout to innervate richly the skin anterior to the 
external nares. Its terminal branches are shown in Plate 2, fig. 4, but 
not in Plate 3, fig. 6. In its course it keeps close to the internasal 
septum and the median dorsal part of the premaxillary bone (Plate 4, 
figs. 8, 9). | 
Il. Ramus mazillaris (Plates 2, 3, figs. 4, 6, 7, mx.). The second 
main branch of the trigeminus is given off from the lateral side of the 
portio major of the Gasserian ganglion. It passes between mm. 
pterygoideus and capiti-mandibularis to reach the posterior ventral 
rim of the bony orbit. It makes a circuit of this ventral rim to the 
anterior side of the orbit where it passes into the marrow cavity of the 
maxillary bone and continues its course in the upper jaw. Besides 
numerous rami distributing somatic sensory components, this nerve 
becomes involved with the superficial sympathetic rami of the head 
in what may be called the “lachrymal plexus,” and with the viscero- 
_ sensory-sympathetic in the orbital plexus. It will simplify the ae- 
count to describe first the somatic sensory rami, as far as possible, as 
though the plexus did not exist and give an account of the latter 
separately. 
The following branches are given off from the ramus maxillaae 
(a) the first branch (mz.!) is given off from the dorsal side. It passes 
around the anterior side of the m. capitis mandibularis and turning 
back supplies the skin (Plate 2, fig. 4; Plate 3, fig. 6). In its course 
it crosses the sympathetic rami in the lachrymal region, but its cutane- 
ous fibers do not mingle. In some dissections it appears to be inde- 
pendent, although in figure 7 it joins the lachrymal plexus in such a 
way that its terminal ramus could not be identified. (b) The second 
branch (ma. 2) also passes across the plexus, where it is difficult to 
follow it in sections, but a dissection, upon being cleared and mounted, 
