xii PHYLUM CHORDATA 539 



like elements. The eyes are small, the auditory pinna well 

 developed. The surface is devoid, or nearly devoid, of hairs, 

 and the skin is enormously thick, and in some species 

 thrown into deep folds. The tail is narrow and of moderate 

 length. 



The hyraxes are small, somewhat rabbit-like animals, 

 with slender limbs and vestigial tail. There are four func- 

 tional digits in the manus and three in the pes, all provided 

 with short flat nails, except the innermost of the pes, which 

 has a curved claw. The body is covered with soft fur. 



The elephants, the largest of existing terrestrial mammals, 

 have the limbs much more typically developed than in the 

 true Ungulates, there being five comparatively short digits, 

 enclosed in a common integument, in each foot, all of them 

 in the fore-, and three or four in the hind-foot terminating in 

 a broad flat nail. The limbs are very stout and pillar-like, 

 and the thigh and leg when at rest are in a straight line 

 instead of being, as in the Ungulata vera, placed nearly at 

 right angles to one another a circumstance which gives a 

 characteristic appearance to the hind-quarters. The nasal 

 region is produced into a proboscis or " trunk," a mobile 

 cylindrical appendage, longer than the rest of the head, at 

 the extremity of which the nostrils are situated. There is 

 in the male a pair of enormous tusks, the incisors of the 

 upper jaw. The eyes are small, the pinna of the ear enor- 

 mous. The tail is small. The skin is very thick and pro- 

 vided with only a scanty hairy covering. 



In the Carnivora the typical number of digits is sometimes 

 present, or, more usually, there are five in the fore- and four 

 in the hind-foot, or four in both. The extremities of the 

 digits are provided with compressed curved claws, which 

 may be very long and sharp, when they are capable, when 

 not in use, of being retracted into a sheath of skin situated 



