HYRACOIDEA. 599 



it gives out a musky odour. Like the Reindeer, the Musk-ox 

 had formerly a much wider geographical range than it has at 

 present ; the conditions of climate which are necessary for its 

 existence having at that time extended over a very much 

 larger area than at present. The Musk-ox, in fact, in Post- 

 tertiary times is known to have extended over the greater part 

 of Europe, remains of it occurring abundantly in certain of 

 the bone -caves of France. Good authorities regard the Musk- 

 ox as being a sheep, and therefore truly referable to the 

 Ovidce. 



CHAPTER LXXVIII. 

 HYRACOIDEA AND PROBOSCIDEA. 



ORDER VII. HYRACOIDEA. This is a very small order which 

 has been constituted by Huxley for the reception of two or 

 three little animals, which make up the single genus Hyrax. 

 These have been usually placed in the immediate neighbour- 

 hood of the Rhinoceros, to which they have some decided 

 affinities, and they are still retained by Owen in the section of 

 the Perissodactyle Ungulates. 



The order is distinguished by the following characters : 

 There are no canine teeth, and the incisors of the upper jaw 

 are long and curved, and grow from permanent pulps, as they 

 do in the Rodents (such as the Beaver, Rat, &c.) The molar 

 teeth are singularly like those of the Rhinoceros. According 

 to Huxley, the dental formula of the aged animal is 



. 2 2 oo 44 33 



i - - \ c : pm - - : m - = 76. 

 2 2 > o o> 44 33 



The fore-feet are tetradactylous, the hind-feet tridactylous, 

 and all the toes have rounded hoof-like nails, with the ex- 

 ception of the inner toes of the hind-feet, which have an 

 obliquely- curved nail. There are no clavicles. The nose and 

 ears are short, and the tail is represented by a mere tubercle. 

 The placenta is deciduate and zonary, whereas in the Ungulates 

 it is non-deciduate. 



Several species of Hyrax are known, but they resemble one 

 another in all essential particulars. They are all gregarious 

 little animals, living in holes of the rocks, and capable of 

 domestication. One species is said to be arboreal in its 



