COMPENDIUM OF GENERIC DISTINCTIONS. 



Genus. Aulac6dus. 



Teeth. Incisors broad and short, brown in front, 

 three furrows in those of the upper jaw. Molars 

 with four folds of enamel. 



Limbs. Fore-feet with thumb and outer toe short. 

 Hind-feet with four toes. 



Tail. Rather short, slightly covered with hair. 



Fur. Composed of flattened and grooved hair, 

 or grooved spines. 



Habitat. Southern Africa. . 



** 



Family. HYSTR?CID^. 



Teeth. Incisors smooth and large; molars with 



44 



waving strips of enamel, always . 



44 



Limbs. Fore-feet with four toes, a wart instead 

 of the thumb-joint. 



Fur. None, being replaced by strong and sharp 

 spines. 



Sub-family. Hystricina. 



Teeth. Molars with undivided roots, set deeply 

 in the bone ; third molar placed under the anterior 

 margin of the orbit. 



Limbs. Feet with soles smooth, but grooved. 



Genus. Hystrix. 



Limbs. Hind-feet with five toes. 



Tail. Not prehensile. 



Habitat. Parts of Europe, Africa, and Asia. 



Atherura is included in this genus. 



Sub-family. Cercolablna. 



..Teeth. Molars with short, divided roots, set 



shallow in the bone. First molar placed under 



margin of orbit. 



Limbs. Feet with warty soles. 



Genus. Erethizon. 



Tail. Short and spined. 

 Limbs. Hind-feet with five toes. 

 Fur. Long hair, interspersed with short, sharp 

 spines. 



Habitat. Canada. 



Genus. C ercolabes. 



Tail. Long and prehensile. 

 Limbs. Hind-feet with four toes. 

 Habitat. Brazils. 



Sub-family. Subunguldta. 



Teeth. Molars complex. 



Limbs. Fore-feet with four or five toes, hind-feet 

 with three or four. Claws large and keeled above. 



Genus. Dasyprocta. 



Head. Lips cloven. 



Limbs. Fore-feet with four toes and a wart for 

 the thumb ; hind with three toes. 

 Tail. Represented by a small, naked tubercle. 

 Fur. Hair long on hind-quarters. 

 Habitat. Brazils. 



Genus. Coelogenys. 



Head. Lip cloven. Great development of zygo- 

 ma, lined with a fold of skin. Cheek-pouches. 



Limbs. Fore-feet with four toes and nailed wz 

 for thumb. Hind-feet with three toes. 

 Tail. Very short. 

 Habitat. Tropical America. 



Genus. Hydrochcerus. 



^ Teeth. Slight longitudinal groove on upper in- 

 cisors. Molars without roots. 



Head. Thick, lips not cleft. 



Limbs. Feet partially webbed. Fore-feet with 

 four toes, hinder with three. 



Tail. None. 



Habitat. /Tropical America. 



Genus. Cavfa. 



Teeth. Incisors smooth. Molars without roots, 

 and curiously laminated. 



Head. Ears short and rounded. 



Limbs. Feet cloven : fore-feet with four toes, 

 hinder with three ; feet short. 



Tail. None. 



Habitat. Brazils. 



Family. LEP<5 RID^E. 



Teeth. Four incisors in upper jaw, a pair 

 these teeth being placed behind the two usual in- 

 cisors. Molars without roots, formed of two lamime. 



Limbs. Fore-feet with five toes, hinder with 

 four ; soles hairy. 



Tail. Short, or absent. 



Genus.' Lepus. 



2 2 3 3 3 3 



Teeth. I. , P. , M. -, - 28. 



i i 22 33 



Head. Ears long. 



Limbs. Hind-legs longer than fore-limbs. 



Tail. Short, and curved upward. 



Habitat. Europe, Asia, Africa, and America. 



Family. } 



Limbs. Fore-feet short. Hind-feet long, and 

 formed for leaping. 



Tail. Long, and thickly haired. 



Sub-family. ChinchilUna. 



Teeth. Incisors smooth. Molars rootless, and 

 composed of narrow lamina?. 



Teeth. M. 



Genus. Chinchilla. 

 44 



44 



-, three laminae in each. 



Head. Ears large, rounded, and scantily haired; 

 whisker hairs very long. 



Limbs. Fore-feet with five toes, hind with four. 

 Habitat. Peru. 



Genus. Lagotis. 



Head. Ears long, like those of the hare 

 Limbs. Fore-feet with four toes. 

 Habitat. Peru. 



Sub-family. Dipina. 

 Teeth. Molars with roots and complex. 



