ELEPHANTS, RHINOCEROSES, AND HORSES 261 



man in these islands the mastodon need not be described here 

 in detail. 



Family : ELEPHANTID.E. THE ELEPHANTS 

 The family of the Elephants, besides the genera Mastodon and 

 Stegodon, includes that of the elephants proper, Elephas, a genus 

 which almost certainly originated from a Stegodont form of 

 mastodon in Eastern Asia, and spread thence (firstly in the form 

 represented to-day by the African elephant) into Western Asia, 

 Africa, and Europe. Thus, though Africa was the source of 

 the Elephant sub-order, it was probably not the centre of develop- 

 ment from which the True Elephant genus originated. 



The elephants are not only remarkable by their great bulk 

 (though some of their extinct forms in the Mediterranean basin 

 and in Europe degenerated into pygmy types not larger than 

 sheep or Shetland ponies), but also for the prolongation of the 

 nose into a long, prehensile trunk. It is thought by some 

 zoologists that the original Proboscidean had rather a long, 

 tapering skull, the head ending, no doubt, in a prehensile snout 

 such as has been developed in the pigs, in the insectivores, in 

 the tapir, and in some other mammals. Owing to the disuse 

 of the front teeth, with the exception of the long central pair of 

 incisors, the bones of the skull gradually sank backwards, leaving 

 the premaxillary region (namely, the front portion of the head) 

 unsupported. Their theory, therefore, is that the trunk of the 

 modern elephant represents not only a much-elongated nose, 

 but the fleshy portion of the original upper jaw and ribbed palate. 

 The elephants have retained the five toes on hind and fore 

 feet. The structure of their limbs is unique, the skeleton of 

 the limb being almost perpendicular, almost vertical from the top 

 of the scapula or of the pelvis to the wrist or ankle-joint— that 

 is to say, there is very little bend when the animal stands erect, 

 either at the knees or at the elbow. The elephants are without 

 collar bones. The nasal opening in the skull, also, is situated 

 very high up, somewhat as in the whales (this, however, is a 

 feature which is met with not only in the whales, but in at least 



