willard: cranial nerves of anolis carolinensis. 77 



nerves will be given. It is based on the details of this nerve complex 

 as worked out in six eases, and gives the features common to all. 



There is much variation in the details of the connection between 

 nerves IX and X. Without reference, for the time being, to the anas- 

 tomoses of uncertain significance, the essential features of the two 

 nerves may be stated as follows: 



(a) Nerves IX and X arise each by several separate roots, at least 

 one root of each nerve being motor. The component character of 

 each nerve appears to be the same, although X exceeds IX in the 

 number of both its sensory and motor components. The ganglion 

 of IX (Plates 2, 7, figs. 4, 23) lies some distance from the brain, as 

 already stated, and probably is not strictly homologous with the 

 ganglion of X, the jugular, which is just outside the foramen. 



(b) The coarser motor fibers in each case are readily seen to pass 

 through their respective ganglia. 



(c) There is a postganglionic division of each nerve which results 

 in each case in two bundles; a bundle of mixed coarse and fine fibers 

 and a bundle composed exclusively of fine fibers. 



(d) The mixed bunrlles come together (as pharyngo-laryngeal 

 branch) and then join XII for distribution on the floor of the pharynx. 



(e) The fine fibered bundle of IX is very small and joins the sym- 

 pathetic trunk, from which it may later separate, along with sympa- 

 thetic elements, to reach palatine VII. 



(f ) The purely sensory bundle of X is a large one, and passes caudad 

 to its trunk ganglion, ganglion nodosum (gn. nd.) ; it then divides 

 (Fig. L) to form the ramus recurrens X and the ramus visceralis dis- 

 tributed to the lungs, heart and alimentary canal. 



(g) In all cases studied except one IX and X show an anastomosing 

 ramus (Fig. 4, comn. IX-X) which connects a preganglionic point of 

 IX with a postganglionic point of X. The one exception is shown in 

 Figure K, already referred to, where there is no connection whatever 

 between IX and X proximal to the union of the phar^^^lgeal and lar^m- 

 geal rami. 



2. A VESTIGIAL DORSAL GaNGLION ON THE RoOTS OF THE VaGUS. 



There was found in several cases in Anolis a very small group of 

 ganglion cells situated on the dorsal side of one of the roots of nerve X. 

 Sucla gangla were studied in three cases. In two cases they were situ- 

 ated upon the largest, most posterior root, which carries the motor 

 fibers. In the third case the ganglion, being smaller than in the others, 

 consisted of only three or four cells located on the small middle root. 



