378 COMPARATIVE SPLANCHNOLOGY. 



especially in the male, having the character of tusks ; the lower ones are the 

 largest, and curve outwards aiid upwards ; the upper pass outwards and down- 

 wards. The tusks continue to grow during the life of the animaL 



The molars also vary in shape, gradually increasing from the first to the last,, 

 which is large and strong ; they are intermediate between herbivorous and 

 carnivorous, and somewhat resemble the human teeth. The first, which ia 

 small, and corresponds to the v/olf-tooth of the horse, is a permanent or trae 

 molar, the next three are the premolars, and the remaining three, true molars. 



The stomach is simple and somewhat capacious ; it consists, as in the horse, of 

 two divisions, cardiac and pyloric, the latter being the smaller, but the division 

 externally is marked by a much more distinct constriction. At the upper and 

 left portion of the cardiac half is a small diverticulum or cul-de-sac. The 

 oesophagus is infundibuliform at its termination. The mucous membrane, for 



Cfficum and colon of a Hog— inflated. 

 d, Kectum. 



the most part villous in its structure, forms two folds which extend from the 

 cardiac towards the pyloric orifice, representing undeveloped oesophageal 

 pillars and canal. 



In the general sense the intestines resemble those of the ruminant, but only 

 the posterior part of the colon lies between the folds of the mesentery. A 

 Peyer's patch of enormous size occurs at the terminal portion of the small 

 intestine. The ccecum resembles that of the horse in having longitudinal 

 muscular bands, three in number, and transverse constrictions, and that of the 

 ruminant in its shape, and the direct continuity of its canal with that of the 

 colon ; the latter is coiled in a similar manner to that of the ruminant. 



