198 THE ANATOMY OF THE HORSE. 



a branch of the lingual nerve turns round it. The duct will be readily- 

 recognised and distinguished from a blood-vessel by its slender and 

 uniform calibre, and by its clear contents. 



The Lingual or Gustatory Nbeve is a branch of the 5th. It contains 

 here, however, not only its own proper fibres, but also fibres derived from 

 the 7th through the clwrda tympani, which joins it in the first part 

 of its course. At the root of the tongue it passes between the mylo- 

 hyoideus and the stylo-glossus and great hyo-glossus muscles, until it 

 passes to the inner side of the sublingual gland. There it turns 

 forwards between the muscles, and is continued in a flexuous 

 manner, giving ofi^ branches that are distributed to the mucous mem- 

 brane of the tongue in its lower two-thirds. At the base of the 

 tongue it detaches a few filaments to the mucous membrane there, to 

 Wharton's duct and the submaxillary gland, and a larger branch for the 

 sublingual gland and the adjacent mucous membrane. 



The Hypoglossal (12th) Nerve (Plate 30) will be found at the base 

 of the tongue, in front of Wharton's duct, where it is included between 

 the mylo-hyoid and great hyo-glossus muscles. Passing to the inner 

 side of the sublingual gland, it comes into relation with the lingual 

 nerve, and divides. The branches of the hypoglossal are motor to the 

 muscles of the tongue. 



The Submental Artery. This vessel, a branch of the submaxillary, 

 has already been seen in the dissection of the intermaxillary space. It 

 leaves the space by passing forwards through the mylo-hyoid muscle, 

 and extends along the posterior border of the sublingual gland, into 

 wliich, and the muscles, it throws branches. It extends beyond the 

 lower extremity of the gland, and terminates in small branches to the 

 mucous membrane. 



The Submental Vein. This is relatively larger than the artery, 

 which it accompanies. 



The Lingual Vein (Plate 30). This vessel will be found at the 

 upper part of the tongue, in company with the gustatory nerve. It 

 receives branches from the soft palate and pharynx, and joins the buccal 

 vein. 



The lingual artery (which runs its course separate from the vein of 

 the same name) and the 9th nerve cannot be followed until some of the 

 muscles have been dissected. Plate 31 will serve as a guide in the 

 isolation of these muscles. 



The Mylo-hyoid Muscle has already been seen in the dissection of 

 the intermaxillary space, and it is now seen on its opposite aspect. It 

 is described at page 171. 



The Stylo-glossus. {Hyo-glossus longusoiVerci-vAW). (Plate 31). This 

 is a long, riband-shaped muscle, arising by a thin aponeurotic tendon 

 from the outer surface of the great comu of the hyoid bone near its 



