32 ANATOMY OF THE WOOD RAT 



M. hyoglossus (fig. 8) has origin along the anterior 

 border of the entire hyoid, including the greater cornu and 

 the body. Near the origin it is in contact with its fellow 

 of the opposite side, but it at once diverges, passing cranio- 

 laterad deep to the styloglossus, and is inserted upon the 

 lateral margin of all but the anterior portion of the base 

 of the tongue. 



M. genioglossus (figs. 8, 24). The more anterior and 

 superficial part of this muscle, especially in Teonoma, is 

 partially divisible into two, parallel portions, between which 

 passes a branch of the hypoglossal nerve. It has a rela- 

 tively weak origin from the symphysis, and at the other 

 extreme, is definitely attached to the hyoid, deep to the 

 last. Closely pressed to and partly integral with its 

 antimere, it constitutes the medial portion of the tongue. 



The innervation of these three tongue muscles is by the 

 N. hypoglossus. 



MUSCLES OF THE BODY 



The muscles of the body are gathered under the following 

 headings : 



I. Muscles of the neck 

 II. Muscles of the trunk 



I. MUSCLES OF THE NECK 



The muscles of the neck are again divided into 



1. Superficial group 



2. Supra- and infrahyoid group 



3. Deep lateral and subvertebral group 



1. Superficial group 



These are but two in number, as follows: 



Mm. sternomastoideus 

 cleidomastoideus 



