willard: cranial nerves of anolis carolinensis. 91 



margin by passing around the genioglossus muscle (Plate 4, fig. 10, 

 Ing. I. XII'). The other division (Ing. I. XI P) of the lateralis XII 

 combines with lingual V and the two mingled components are dis- 

 tributed together (Plate 2, fig. 5). The dorsal musculature of the 

 tongue begins here to take on the crossed arrangement of its fibres 

 (p. 35), and this seems to be related to the presence of papillae on the 

 surface characteristic of the anterior end of the tongue (Plate 4, fig. 9). 



In the distribution of the three main divisions of XII, it is important 

 to note how each is quite definitely Umited to a particular part of the 

 musculature, and that the part of XII which is mingled with V inner- 

 vates only the strictly intrinsic musculature, for the most part those 

 short muscle fibers which are inserted into the mucous membrane of 

 the papillae-bearing dorsal surface. 



These papillae deserve special stucly l:)ecause of certain peculiari- 

 ties in their finer structure. These conditions were in part brought 

 out in the unstained material. The muscle fibers, which show a high 

 degree of dift'erentiation between the light and dark transverse bands, 

 extend all the way to the tip of the papillae, and meduUated nerve 

 fibers could also be followed the same distance. Inasmuch as these 

 somatic motor and general cutaneous fillers are approximately of the 

 same size, it is not possible to distinguish between them by this 

 criterion. It is fair to assume, however, that the fibers at the ends of 

 the papillae are sensory, for, from what we know of the innervation 

 of striated muscle, it is not to be expected that the muscle fibers are 

 innervated at their scattered distal ends rather than at a more proximal 

 point, where they are closer together and nearer the source of nerve 

 supply. We know also that nerve fibers of the general cutaneous 

 type have come into this region in the lingual branch of ramus maxil- 

 laris V, and presumably they must reach the surface. No taste buds 

 were found among these papillae, although at the sides of the tongue 

 such buds were found among the tubular glands.^ In a region where 

 these papillae are best developed they are flattened at the end, where 

 the epithelium is of the stratified columnar type. The sides are cov- 

 ered with simple glandular epithelium. The flattened ends show 

 many cells extending out as though protruding individually. The 

 free ends, being knob-like, contain the nuclei, while the base is attenu- 

 ated into a slender column. The result is a sort of tuft of knobbed 

 projections forming the end of each papilla. It is to this flattened 

 terminal portion that the muscle and nerve fibers pass. 



' Later study on the histology of the tongue has disclosed a few papillae 

 bearing single taste buds in their flattened ends. 



