THE SUIDtE. 313 



The stomach is more or less complex. The caecum, though 

 well developed, is smaller than in the Perissodactyla. 



The mammce are inguinal or abdominal. When horns are 

 present, they are double, supported, wholly or partly, by the 

 frontal bone and provided with an osseous core, which is 

 almost always an outgrowth from that bone. 



The Artiodactyla are divisible into the Non-U uminantia 

 and the Rwninantia. 



A. The N'on-Uuminantla usually have more than one pair 

 of incisors in the upper jaw. The molar teeth have either a 

 mammillate, a transversely-ridged, or a rhinocerotic pattern. 

 In only one genus, Dicotyles^ are any of the metacarpal or 

 metatarsal bones anchylosed together. They are devoid of 

 horns, and the stomach has rarely more than two divisions. 



The Non-Iiimiinantia are divisible into three families: 

 The Suidoe^\hQ IIlppopotamidcB^2iwdi the Anoplotheridm ; but 

 more or fewer of the members of this last group may have 

 ruminated. 



a. The SuidcB have the skin of moderate thickness and 

 hairy ; the limbs slender, and the third and fourth toes con- 

 siderably longer than the second and fifth. The teats are 

 abdominal, and there is a scrotum. The dental formula varies 

 considerably, but the molars hav^e a multituberculate or trans- 

 versely-ridged grinding surface. 



In the genus Siis^ the dental formula is ^. ^ c. ~-^ pjn. 



4-4 3-3 



4-4 ^- 3-1' 



Bv way of contrast with the Horse, I add some more de- 

 tailed statements regarding the anatomy of the Pig as a com- 

 mon and very good example of an Artiodactyle. The Pig has 

 seven cervical vertebrae, nineteen* dorso-lumbar, of which 

 fourteen are dorsal, four sacral, and twenty to twenty-three 

 caudal. The atlas has wide oblique alas, as in the Horse. 

 The centra of tlie other cervical vertebrae are short, with 

 nearly flat articular surfaces, and this flatness is retained in 

 the dorso-lumbar res-ion. The cervical and dorsal vertebrae are 

 provided with long spines, that of the first dorsal vertebra 

 being the longest of all. Up to the twelfth dorsal the spines 

 all slope backward ; beyond it they slope forward, if at all. 



In the ninth dorsal vertebra the postzygapophysis presents 

 an articular surface on its dorsal side, and the prezygapophysis 

 of the tenth vertebra bends round so as to overlap this surface. 

 This character is continued in the succeeding vertebrae as far 



* Exceptionally, the number may be increased to twonty-two. 

 14 



