MAM:MALS 446 



(v) HOMiNiD^, with several extinct genera {Pithecanthropus, etc.) and 

 the single living genus, Homo. 



(5) XENAKTHEA — these comprise three distinct sub-orders : 



(a) the solitary nocturnal, arboreal sloths (bradypodid^) (3-toed 

 Bradypus, or 2-toed Choloepua) of S. and Central America, vegetarian in habit, 

 which spend a sluggish life hanging from the branches of trees (Fig. 751) ; 



(b) the terrestrial or arboreal ant-eaters (MYRMECOPHAGiDiE) of neo- 

 tropical distribution ; 



(c) the omnivorous nocturnal armadillos (dasypodid^), mainly of S. 

 America, with a dermal armature of bony scutes, which actively run and burrow. 



(6) PHOLIDOTA. The small family of burrowing, termite-eating, scaly 

 pangolins {Manis) of Ethiopia and the East. 



(7) TUBULiDENTATA. The equally small family of shy. nocturnal, termite- 

 eating aard-varks (Orycteropus) of Africa, living in burrows. 



The Xenarthra, Pholidota and Tubulidentata used to be classed together 

 as EDENTATA Owing to the simplicity of their teeth or the lack of them. 



(8) RODENTIA, the largest order of Mammals, comprising more than 4,000 

 species, mainly small, terrestrial and vegetarian, which gnaw their food in a 

 characteristic way. They are represented by two sub-orders^ according to their 

 dentition : 



(a) those provided with two pairs of upper incisors (lagomorpha) — the 

 rabbit {Oryctolagus), the hare (Lepus) and the pikas or calling hares (Ochotona) ; 



(b) those provided with a single pair of upper incisors, which are con- 

 veniently divided into three groups : 



(i) the sciurojiorpha — the common squirrel (Sciurus), the souslik 



or ground squirrel (Citellus), the prairie-dog {Cynomys), the 



flying squirrel (Pteromys), the marmot (Marmota), the beaver 



(Castor) ; 



(ii) the MYOMORPHA — the rat (Rattus), the mouse (Mus). the vole 



(Microtua) ; 

 (iii) the hystricomorpha — the porcupine (Hystrix), the guinea-pig 

 (Cavia), the chinchilla, the vizcacha [Lagostomus) , the coypu 

 (Myocastor), and others. 



(9) CARNivoRA. A large amorphous order of active and fierce flesh-eaters 

 of wide distribution and mostly terrestrial. It is comprised of 2 sub-orders : 



(o) the terrestrial fissipedia, including 7 families : the cat-like Felidae 

 (cat, lion, tiger, leopard, cheetah, jaguar, lynx), the Viverridae (civet cats, mon- 

 goose, etc.), the Hyaenidae (hyaenas), the dog-like Canidae (dog, wolf, jackal, 

 fox, etc.), the bear-like Ursidae, the Procyonidae (Himalayan nandas, and the 

 American raccoon and coati), and the Mustelidae (otter, sea-otter, skunk, badger, 

 marten, polecat, ferret and weasel, etc.) ; 



(6) the aquatic pinnipedia, marine flsh-eating Carnivores, clumsy on 

 land where they come for breeding purposes : Phocidae (seals), Otariidae (sea- 

 lions or eared-seals), and Odobaenidae (walruses). 



(10) artiodactyla. Even-toed hoofed animals, terrestrial and herbivorous 

 in habit, wherein the hoof is formed by the third and fourth digits showing a 

 cleft between. Of these there are four extant groups : 



(a) the suoiDEA (pigs and boars, Suidae ; peccaries of America, 

 Dicotylidae ; and the African hippopotamus) ; 



^ The Lagomorpha are now generally accepted as a separate order. 



