Book Notices. 501 



The first few pages are devoted to the elephant, cousin of the extinct 

 mastodon, and differing from it chiefly in the structure of the teeth , 

 "The first and most obvious peculiarity in regard to its dentition is 

 to be found in the tusks, which correspond to one of the pairs of 

 upper teeth in man, and also to the single pair of such teeth in the 

 Rodents (rats, hares, etc.) Moreover, these teeth, like the incisors 

 of the Rodents, grow continuously through the life of the animal, owing 

 to the circumstance that the pulp cavity at their base always remains 

 open and has a permanent connection with the soft structures of the 

 gum. In our own teeth, on the contrary, the pulp cavity closes at a 

 certain period, after which there is a total cessation of growth." 



A rude shock to our common ideas of elephantine nature is afforded 

 by the extinct elephants of Malta, which show us that gigantic size is 

 not a necessary concomitant of the group, and that when the area in 

 which a species dwelt was small the size of the species itself was pro- 

 portionately reduced. These little Maltese elephants were very closely 

 allied to the living African species, but whereas "Jumbo" attained 

 eleven feet in height, and wild specimens of the African elephant may 

 be still larger, the smallest of the Maltese species was scarcely taller 

 than a donkey. So small, indeed, are the bones and teeth of this 

 species, exhibited in the National History Museum, that it is sometimes 

 difficult to convince people that they really belong to elephants at all. 



As regards their distribution, elephants and mastodons formerly 

 roamed over the whole world, with the exception of Australia; true 

 elephants ranging over the whole Northern Hemisphere, while masto- 

 dons extended as far south in the New World as the confines of 

 Patagonia. It is in the north-east of India, Burma, and the Islands 

 of the Malayan region that the fossil elephants connecting the living- 

 species with the mastodons are alone found ; and it is thus probable 

 that from these regions the true elephants migrated westward into 

 Europe and Africa, while the mammoth, in later times, crossed from 

 Asia into Alaska by way of Behring Strait. That the mammoth, 

 which ranged from the Arctic regions to the Alps and Pyrenees, was a 

 contemporary of the primeval hunters of Europe, is now a well- 

 established fact ; but it appears that throughout the Old World 

 mastodons had utterly died out before the advent of man. In the 

 New World, however, the continuity between the old and the new 

 fauna was more fully sustained, the Missouri mastodon having survived 

 well into the human period, so that we have in this survival a good 

 instance of the vast changes that have taken place in the fauna of the 

 globe within what we may metaphorically call the memory of man. 



In organized nature, two factors are in constant opposition ; one being 

 adherence to a particular type of structure — the other, adaptation to 

 -a particular mode of life. The resultant of these two forces is usually 

 found to be, that animals living similar modes of existence become 



