THE AGOUTI FAMILY. 



169 



a dark gray on the back, but the belly is white, 

 and there is* a white stripe across the nose 

 and cheeks. 



THE AGOUTI FAMILY 



(SUBUNGULATA). 



The South American family of the agoutis 

 is distinguished 

 from all the other 

 families by the pe- 

 culiar structure of 

 the toes, which in- 

 stead of nails or 

 claws carry a sort 

 of hoofs. This 

 structure of the toes 

 is very conspicuous 

 in the largest mem- 

 ber of the family, 

 and indeed the 

 largest of all ro- 

 dents, the capybara. 

 In this animal the 

 last phalanx on all 

 the toes appears in 

 the skeleton round- 

 ed, flat, and spongy, 

 as in the tapirs, 

 and it is encased by a horny hoof, which 

 is likewise flat and rounded. In the other 

 genera this structure of the toes is not so 

 manifest. The hoof stands erect in the form 

 of a ridge or keel, and is prolonged beyond 

 the bony phalanx, only the last part of which 

 is inclosed by it, and as it is also a little 

 curved it presents something of the appear- 

 ance of a claw. In this family there are 

 accordingly transitional forms, which show 

 that the distinction between hoofed and clawed 

 mammals (Ungulata and Unguiculata) is by 

 no means so fundamental as has been repre- 

 sented. 



All the Subungulata have a rather coarse 

 fur, feet naked on the soles, and a mere stump 

 for a tail, often scarcely projecting beyond the 



Vol. II. 



pelvis. The collar-bones are altogether want- 

 ing. These animals are extremely stupid and 

 indolent. The development of the ovum and 

 the embryo, if we may judge from the capy- 

 bara, presents some remarkable peculiarities. 

 The dentition is far from uniform. There 

 are always, indeed, four cheek-teeth in each 

 half of each jaw ; but these are so varied in 



structure that the 

 family can be di- 

 vided into two 

 groups in accord- 

 ance with these dif- 

 ferences. 



In the first group 

 the cheek-teeth are 

 arranged in two 

 parallel rows, and 

 have distinct roots, 

 which, however, 

 are not completely 

 closed. The sur- 

 face of the crown 

 when worn flat ex- 

 hibits intricate folds, 

 so that it acquires 

 the appearance of 

 a coarse fabric 

 which has been 

 lined and then folded twice. 



The Agoutis (Dasyprocta) belong to this 

 first group. These animals, which have some- 

 times been called "golden hares," have a 

 thickset body, which is high and arched be- 

 hind. The muzzle is somewhat blunt; the 

 ears are small and rounded; the legs, especi- 

 ally the hind ones, long and thin, the tail- 

 stump naked. The fore-feet have four toes 

 with broad, strong, slightly curved nails, and 

 a rudimentary first digit covered with a flat 

 hoof; the hind-feet have only three toes, but 

 these are very long and are inclosed in rather 

 long claw-like hoofs. The large incisors are 

 yellow in front; the cheek-teeth have two 

 bundles of simple folds. The species shown, 

 the Agouti Proper or Golden Agouti (Z?. Aguti), 



54 



