willard: cranial nerves of anolis carolinensis. oy 



dorsal side of this muscle to join the dorsal ramus of the first spinal 

 nerve, with which its terminal fibers become mingled (Plate 3, fig. 6, 

 spi. d. 1). It is anticipated that, upon careful study of the brain with 

 reference to the nucleus of XII, some difference in origin of these two 

 bundles {orv. I. XII and crv. d. XII) as compared with XII proper, 

 will be demonstrable. 



In its course around the pharynx to reach the ventral side of the 

 neck XII crosses dorsad of the thymus gland (Plate 7, fig. 24, gl. thy.), 

 and also of the visceral ramus of X and the sympathetic trunk, which 

 lie close together on the dorsal side of this gland (Plates 2, 3, figs. 

 4, 6, and 7, vsc. X and sy.) . XII, turning ventrally, passes between the 

 thymus gland and the jugular vein mesad of all muscles. Section 

 1595 (Plate 7, fig. 24) falls in a plane just caudad of XII so that no 

 part of it appears; the other structures referred to show well in this 

 section. Section 1480 (Plate 7, fig. 23) shows XII after it has attained 

 its ventral position. This is reached by crossing the end of the first 

 cerato-branchial on its lateral side. Nerve XII then takes a direction 

 cephalad (Plate 7, figs. 22, 23) between the cerato-hyal (ker-hy.) and 

 the first cerato-branchial {ker-brn. I), on the ventral side of the 

 cerato-hyoideus (hyo-glossus) muscle. Its direction from this point 

 onward is cephalad and mesad along the lateral edge of the genio- 

 glossus muscle and the median side of the cerato-hyal. As it passes 

 forward it comes to lie on the ventral side of the genio-glossus (gen-gls.), 

 where it parallels the mandible to a point as far forward as the basi- 

 hyal (Plate 6, figs. 16-18). Here we find a division of the main 

 trunk into two rami of about equal size. The median one immediately 

 divides, so we then have a three-fold division (Plate 5, fig. 12, big. I. 

 XII, lug. i'm. XII, and Ing. m. XII) of the main trunk, the lateral one 

 containing about half the fibers. From this point forward these 

 three main rami diverge and pass up into the tongue musculature for 

 distribution (Plate 2, fig. 5). This course of the main trunk and termi- 

 nal divisions of XII has been described without reference as yet to 

 certain small rami which it gives off. The branches of XII will now 

 be described in more detail: 



Distribution of the hypoglossal nerve, (a) Ramus pharyiigo-laryngeus 

 {phx-lar'.). Although r. pharyngo-larvTigeus is given off as a branch 

 of XII, the principal, if not the sole, source of its fibers is from nerves 

 IX and X, as described in connection with the account of those nerves. 



(6). Between (a) and the main divisions of XII there are given 

 off several very small rami, which inner\ate the muscles between 

 which the hypoglossal nerve passes. The first of these (Plate 2, fig. 5, 

 XII ^) supplies the cerato-mandibularis 1 (Fig. 18) in its posterior 



