Dissection of Sheep^s Head, 257 



The anterior and inferior surface of the velum forms the 

 posterior boundary of the mouth, and is united laterally to 

 the base of the tongue. Between the velum and the base of 

 the tongue are two lateral spaces, in each of which are two 

 or three openings, the mouths of the ducts from the Tonsils^ 

 each tonsil being a collection of follicular capsules. 



The Hard Palate^ or anterior part of the roof of the mouth, 

 consisting of the palatine bones and palatine processes of the 

 superior maxilla, is covered by a dense membrane, equally 

 divided by a median longitudinal ridge, which terminates 

 anteriorly in a small tubercle. From this ridge proceed 

 transverse ridges, dividing the palate into a number of super- 

 ficial folds, the edge of each posterior fold underlying the 

 posterior margin of the fold next in front of it, so that an 

 abrupt edge is always presented towards the back of the mouth. 



The Tongue* presents three distinct portions ; the most 

 anterior constitutes the tip, and its upper surface may be 

 called dorsum planum : this portion is limited abruptly 

 posteriorly by the hump or elevation which forms the second 

 portion, and whose upper surface may be denominated dorsum 

 gibbosum : that part which gradually declines to the base of 

 the epiglottis forms the third part, and its surface may be 

 called dorsum radicis. The tip assists in the prehension and 

 mastication of the food ; the gibba, like a piston, pushes the 

 bolus towards the pharyngeal cavity ; while the root, by 

 means of the exterior parts of its muscles, enables the organ to 

 move as if connected by a joint to the hyoid bone. 



In the Human tongue the whole ante- gibbous portion is 

 deficient : it is therefore truncated as compared with the 

 Huminant tongue. It is by means of the ante- gibbous por- 

 tion of the tongue that quadrupeds lap up water. 



The under surface of the tongue is connected laterally to 



* Cf. J. Zaglas. Annals of Anat. and Fhys., 1850. Parts i. and ii. 



T- L 



