OMNIVORA — DIGESTIVE SYSTEMS 



877 



OMNIYORA. 



Fio. 138. 

 Skull of a Hog— showing the teeth. 



DIGESTIVE SYSTEM. 



In the hog the mouth is large, the labial fissures extending far backwards ; the 

 upper lip is confounded with 

 the snout, while the under one 

 is short and pointed. The 

 canal of Jacobson opens to- 

 wards the front of the hard 

 palate by a small orifice. The 

 tongue and velum palati are 

 like those of the smaller 

 ruminants, but the filiform 

 papillae of the former are 

 more developed. 



The parotid and submaxil- 

 lary glands have relative pro- 

 portions similar to those of 

 the ruminant. There are two 

 sublingual glands on either 

 side; one long and straight, 

 situated near the angle of the 

 jaw, and terminating in a 

 single duct, which opens near 

 that of the submaxillary j the 

 other, flat and four-sided, is 

 the true sublingual, r.nd lies 

 in front of the former, open- 

 ing along the lower dental 

 arch by eight or ten ducts. 



The hog is one of the few 

 existing animals which pos- 

 sesses what Professor Owen 

 regards as the typical mammalian number of ieeth; its permanent dental 

 formula is this : — 



Stomach of a Hog— inflated, a. Cardiac portion ; 6, Its 

 accessory cul-de-sac; c, Pyloric portion ; d, Lesser curva>> 

 ture ; e. Greater curvature ; /, (Esophagus ; g, Pyloxio 

 orifice. 



.3-3 



**3:^' 



^ 1-1 ^^ 3-3 ^ 4-4 _ ., 



The incisors differ from each other in a remarkable degree ; the central and 

 lateral ones in the upper jaw resemble the corresponding ones in the horse, 

 having cavities in their tables, while the upper comer incisors are isolated, and 

 small in proportion to the other four. The central and lateral incisors of the 

 lower jaw are long, nearly straight, projecting forwards, and somewhat resem- 

 bling the incisors of the rodent ; the lower corner incisors are also isolated, 

 but smaller than those of the upper jaw. The canine teeth are well developed. 



