52 bulletin: museum of comparative zoology. 



components of the trigeminal nerve will be preceded by a more general 

 statement. The main branches of this nerve correspond quite closely 

 with the typical condition found in lower vertebrates. The ophthalmi- 

 cus profundus, proceeding from its owti independent ganglion, is 

 distributed to the skin of the dorsal surface of the head over an area 

 extending from a post orbital region forward to the tip of the snout, 

 the frontal region receiving its fibers over a special ramus, which leaves 

 the ophthalmic at the ganglion; the rest of the nerve, as the nasalis 

 branch, takes the course through the orbit typical of the profundus, 

 receiving the long root of the ciliary nerve on its way, and supplies 

 the skin of the dorsal surface of the snout and the epithelium of ante- 

 rior nasal chamber. 



The second and third (maxillary and mandibular) branches of the 

 trigeminus join the main trigeminal ganglion as large branches from 

 the upper and lower jaw regions. The maxillary supplies the skin 

 around the eye and the upper and lower lids ; it crosses the floor of the 

 orbit to the upper jaw, in which it runs forward to the tip of the snout, 

 supplying the skin lateral to the jaw and the epithelium of the gums 

 and the teeth. 



The mandibular branch passes down to the lower jaw, which it 

 enters, supplying the skin, gums and teeth in a manner similar to that 

 'described for the upper jaw. It also supplies the anterior regions of 

 mouth and tongue. In this latter distribution it is closely associated 

 with the somatic motor components of XII and the viscero-sensory 

 components of the chorda tympani. Certain plexuses and anasto- 

 moses omitted from this general account will be included in the de- 

 tailed description which follows. 



I. Nervus ophthalmicus yrofundus. This term, as including all the 

 fibers entering the ophthalmic ganglion, has no application in Anolis, 

 as the two main branches (r. nasalis and r. frontalis) do not unite distal 

 to the ganglion. These two branches will be described as the frontal 

 and nasal rami. 



la. Ramus frontalis (/.). — The point where in different reptiles 

 the frontal ramus joins the nasalis is determined somewhat by the 

 relation of the ganglion to the orbit. In Anolis (Plates 2, 3) the 

 orbit is large and the frontal ramus takes rather an abrupt dorsal 

 course to reach the skin posterior to it; the ramus therefore joins the 

 ganglion directly. The frontalis is about half the size of the nasalis. 

 Both are composed of the same kind of fibers, except that the nasalis 

 carries the non-meduUated fibers of the radix longa of the ciliary 

 nerve, which collectively can be recognized from the beginning of the 



