702 MAMMALIA. 



African origin, the wild asses of Africa and Asia ; the striped African 



species the zebras and the (exterminated) quagga. 



Family Rhinocerotidce. There is now but one genus Rhinoceros, 

 species of which occur in Africa and in some parts of India and 

 Indo- Malaya. They are large heavy Ungulates, shy and noc- 

 turnal, fond of wallowing in water or mud, feeding on herbage, 

 shoots, and leaves. The skin is very thick, with scanty hair. 

 One or two median horns grow as huge warts from the snout 

 and forehead. The dentition is very variable, but the back 



teeth are almost uniform, there are no upper canines, but 



sometimes a large lower pair, there are a few incisors, but these 

 are often small and deciduous. 



There are several entirely extinct families of Perissodactyla, such as 

 Lophiodontidae (Eocene), e.g., Lophiodon, Hyracotherium, 



Systemodon, a family perhaps ancestral to most of the 



modern Perissodactyla. 

 Palseotheriidoe (Eocene to Miocene), e.g., Palcsotherium and 



A nch itherium. 

 Other remarkable types 



Ldmbdotherium, Ckalicotherium, Tit another ium, of elephantine 



size, and the specialised Macrauchcnia are referred to 



distinct families. 



Sub-Order HYRACOIDEA. 



Small Rodent-like Ungulates, represented by one genus 

 Hyrax or Procavia, living in rocky regions and on trees 

 in Africa and Syria. The species (14) are adept climbers. 



The upper incisors have persistent pulps and are curved 

 as in Rodents, but they are sharply pointed, not chisel-edged. 

 The outer lower incisors are straight and have trilobed 

 crowns. There are no canines in the second set, but the 

 upper milk canine sometimes persists ; and there is a wide 

 space between incisors and premolars. The back teeth are 

 very uniform and like those of Perissodactyla. The milk 



dentition is - , the permanent is . Hyrax is one of the 



214 2043 



few Mammals in which the first premolar is a replacing 

 tooth. 



In the fore feet, the thumb is rudimentary, the little finger 

 is smaller than the median three, which are almost equal. 

 In the hind feet, which are like miniatures of those of the 

 rhinoceros, the hallux is absent, and the fifth toe is rudi- 

 mentary. There are no clavicles. The tail is very short. 



The brain is like that of Ungulates. The stomach is 



