90 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
region. ‘The second (XII *) goes to the small slip of muscle described f 
as the cerato-mandibularis 3 (Plate 6, figs. 16-19, ker-md.*) sending — 
also a few fibers to the same muscle that receives the first twig. — 
Some distance cephalad a third ramus (XJ %) is given off, which in- 
nervates this first muscle, the most of the bundle, however, passing | 
far forward to reach the portion described as cerato-mandibularis 2 
(Plate 2, fig. 5; Plates 4, 5, figs. 9-12, ker-md.2). Just anterior to . 
this several small branches (Plate 2, fig. 5, XI *) supply the posterior 
portion of the genioglossus. 
It is noticeable that all these small rami to the more superficial 
tongue muscles draw off from XII the largest and most strongly 
medullated of its fibers, although not exclusively fibers of this kind. 
There is no further distribution of fibers of XII from the main trunk, 
which now may be said to supply the tongue proper through the three 
main divisions referred to above. For convenience in description 
these will be described as median, intermediate and lateral rami. 
Ramus lingualis medialis XII (Ing. m. XII). This ramus crosses — 
the ventral side of the main longitudinal tongue muscle, genioglossus, 
to reach the median edge of this muscle. Here, on either side of the 
glossohyal (gls-hy.) and underlying the larynx, begins a mass of muscle 
composed of short vertical fibers (Plate 4, fig. 11, lng. ort.). This forms 
a continuous vertical muscle surrounding the glossohyal as far forward 
as its anterior end, which is well toward the tip of the tongue. The 
median ramus of XII runs the length of this muscle supplying it on the 
way (Plate 2, fig. 5). As the vertical fibers gradually run out, this 
nerve also dwindles. The fibers innervating this muscle are less 
heavily medullated than those of the small rami previously described. 
Ramus lingualis intermedius XII (Plate 2, fig. 5, Ing. Vm. XII). 
This ramus is a little larger than the median one and the fibers are 
larger and more heavily myelinated. It runs cephalad first on the sur- 
face of the muscle genioglossus then within that muscle. This ramus 
appears to supply the genioglossus exclusively. Its course may be 
followed in the drawings of cross sections (Plate 4, 5, figs. 9-12). | 
Ramus lingualis lateralis XII (Ing. 1. XII). This is the largest 
division of XII and the one which forms the anastomoses with the 
lingual branch of V (Plate 2, fig. 5, Ing. V); before this union, however, 
it divides into two rami of about equal size (Ing. 1. XII + and Ing. I. 
XII?) giving off just proximal to the division a small ramus (XI *) 
supplying the longitudinal tongue muscles. Of the two main divisions 
one is distributed at once in a series of branches to the tramsverse 
musculature (Plate 4, figs. 10, 11, Ing. t.) on the upper surface of the 
tongue, the nerve fibers reaching this muscle at its extreme lateral 
