418 UNGULATA 



Rhinoceros. Interval between upper incisors less than the width of 

 the teeth. Lower incisors slightly notched at the cutting edge. 

 Vertebrae : C 7, D 22, L 8, S 6, C 6. Of this form the earliest 

 known species, H. capensis (Fig. 176) is the type. There are several 

 other species, as H. liabessinicus and syriacus, from Eastern Africa 

 and Syria. They inhabit mountainous and rocky regions, and live 

 on the ground. 



Dendrohyrax. 1 Molar teeth having the same pattern as Palceo- 

 therium (except that the third lower molar has but two lobes). 

 Interval between upper incisors exceeding the width of the teeth. 

 Lower incisors with very distinctly trilobed crowns. Vertebrae : 

 C 7, D 21, L 7, S 5, C 10. The members of this section frequent 

 the trunks and large branches of trees, sleeping in holes. There 

 are several species, not distinctly defined, from western and south 

 Africa, as D. arboreus and D. dorsalis. The members of both groups 

 appear to have a power like that possessed by the Lizards called 

 Geckos of clinging to vertical surfaces of rocks and trees by the 

 soles of their feet. 



It should be added that some writers separate three of the 

 African species usually included in Hyrax (viz. H. bocagei, H. bakeri, 

 and H. blainvillei) under the designation of Heterohyrax. 2 



Suborder PROBOSCIDEA. 



m 



This name has been appropriated to a well-marked group of 

 animals, presenting some very anomalous, characters, allied in many 

 respects to the typical Ungulata, but belonging neither to the Artio- 

 dactyle nor Perissodactyle type of that order. It has been thought 

 that they possess some, though certainly not very close, affinities 

 with the Rodentia, and also with the Sirenia. It is certain, 

 however, that the two species of Elephant, which are the sole living 

 representatives of the group, stand quite alone among existing 

 mammals, differing widely from all others in many points of their 

 structure. In some respects, as the skull, proboscis, and dentition, 

 they are highly specialised ; but in others, as in the presence of two 

 anterior venae cavse and in the structure of the limbs, they retain 

 a low or generalised condition. A considerable series of extinct 

 forms, extending back through the Pliocene and Miocene epochs, 

 show the same type under different modifications, and in still more 



another by George, in Annalcs des Sciences Naturclles, 6 i4me ser. torn. i. 1874, in 

 which references to all the previous literature will be found. The mechanism 

 by which the sole of the foot is enabled to adhere to smooth surfaces is fully 

 described by G. E. Dobson, Proc. Zool. Soc. 1876, p. 526. 



1 Gray, Ann. Mag. Nat. Hist. ser. 4, vol. i. .p. 48 (1868). 



2 See a paper by J. V. Barboza du Bocage, in the Jorn. Sci. Phys. Nat. Lisbon 

 (2), vol. i. p. 186 (1889), where a list of all the known species will be found. 



