willard: cranial nerves of anolis carolinensis. 73 



staining medullary sheaths. These fibers are not placed compactly 

 together and there is an appearance as though non-medullated fibers 

 lay between them. The second connection of IX with other nerves 

 occurs at the level of the distal end of the ganglion. Here the sym- 

 pathetic, formed by the union of the "rami communicantes internus 

 et externus IX et VII" {cornn. i. and comn. ex.), joins the bundle 

 of IX on its ventral side and, after contact and some mingling of 

 fibers for the distance of 1/10 mm. becomes free again (Plates 2 and 3, 

 figs. 4, 7). (In dissections, no distinction can be made between the 

 actual mingling of fibers and inclosure within a common sheath). 

 This connection apparently has no relation to the ganglion, for it 

 occurs on the ventral side of the ganglion at a point where the most 

 distal ganglion cells occupy only the dorsal side. After this contact 

 the nerve shows no more connections up to its union with the superior 

 laryngeal X. 



The variability in these connections is further emphasized when 

 figure K is compared with figs. 4-7, Plates 2, 3. In the former the 

 first named connection is absent and the second is accomplished by 

 means of a s-mall ramus joining the sympathetic trunk. 



P. VAGUS NERVE. 



The central connections of the vagus nerve were less fully deter- 

 mined than those of the other nerves, owing to the fact that the roots 

 are extremely small and the few fibers which each contains do not 

 keep together within the brain but separate into even smaller bundles 

 or single fibers. There is also some variation as to the number of 

 roots that could be identified peripherally. There is considerable 

 shifting of central nuclei in the sharp flexure of the hind brain, making 

 it impossible to determine conclusively the origin of efterent fibers 

 from particular cell groups without the aid of the Golgi, or some 

 similar method. 



Roots of the vagus. In series 30 (Plates 2, 3, figs. 4-6) the vagus 

 enters the jugular foramen as three roots (c/. Fig. K) . Two of these 

 appear in Plate 7, fig. 20 {rx. X) ; to avoid confusion of lines, the 

 plottings show only one root for each component. Of the three, 

 the posterior one contains the deeply staining motor roots; the fibers 

 in the other two do not appear to be of uniform character. The middle 

 root is the smallest. The posterior root has its superficial origin along 



