Mammalia: Classification 761 



and last tooth comes into place. The first cheek-tooth is fully developed 

 in an elephant about 3 months old and the fifth tooth comes into use 

 20 or more years later. These "grinders" attain a size consistent with 

 other exaggerated features of the animal. In an old elephant the 

 anteroposterior dimension of the crown of a tooth ranges from 9 to 15 

 inches and the width is about 3^2 inches. The teeth are transversely 

 ridged (lophodont). 



Elongation of the snout to become the proboscis or "trunk" is 

 the elephant's most distinctive feature. The external nares are at the 

 tip of it. Powerfully muscular and equipped with a delicate finger-like 

 process at its tip, the trunk can be used with equal facility for picking 

 up a peanut or a railway tie (for elephants have been trained to assist 

 in heavy construction). 



The auditory pinnae are of impressive size, but the tail is negli- 

 gible. The animal is strictly herbivorous and the stomach is simple — 

 there is no rumination. The skin is much thickened and only very 

 sparsely covered with hair. The brain is well developed, the cerebral 

 hemispheres being strongly convoluted. The high degree of intelligence 

 commonly credited to the animal is probably overrated. 



The elephant is the most highly specialized of modern land mam- 

 mals. Compared to the external configuration of a "normal" mammal, 

 beautifully exemplified in a cat, tiger, or lion, most of the external 

 features of the elephant are grossly exaggerated, but it is done so 

 consistently that the whole seems well proportioned. Even the small 

 tail seems more fitting than a large one would be. The tremendous bulk 

 is not unwieldy; the gait is ponderous but not clumsy. Although the 

 form of the giraffe is functionally intelligible, the ideal mammalian 

 lines seem to have suffered much distortion. There is something ridicu- 

 lous about the giraffe, but the elephant's form expresses efficiency and 

 commands respect. 



There are only two existing species of proboscideans, the Indian 

 elephant (Elephas indicus) and the African (E. africanus). The 

 African is somewhat larger and its pinnae are relatively much larger. 

 The extinct elephant-like mammoths and mastodons existed in 

 both Eastern and Western Hemispheres. A long-haired ("woolly") 

 mammoth inhabited the cold northern regions of both hemispheres. 



Order 16: HYRACOIDEA. To this Order are assigned certain 

 small obscure mammals whose affinities are problematic. About the 

 size of a rabbit, with legs of medium length, very short tail, small 

 pinnae, and prominent incisor teeth, the animal might be taken for a 

 rodent. The dentition as a whole, however, resembles that of an ungu- 

 late rather than that of a rodent. The manus has four functional. digits. 



