220 



ANIMAL LIFE PAST AND PRESENT. 



There is a considerable amount of variation in the 

 structure of the grinding-teeth of the true Elephants, 

 although all of them resemble to a greater or less 

 degree the specimen represented in Fig. 77. In the 

 African elephant, however, the discs of dentine, sur- 

 rounded by their border of enamel, are much wider in 

 the middle than in ^the figured t tooth, andjthus assume 

 a lozenge shape. In this respect, therefore, the African 



G. 7U. The last left upper tooth of a Mastodon, with the cm 

 first ridges perforated by wear. 



1 of the twi 



elephant is a more generalised or old-fashioned kind of 

 animal than his Indian cousin ; and we may observe, 

 in passing, that the African continent is now remark- 

 able for containing a number of old types, such as 

 Hippopotamuses, Giraffes, and Aard-Varks, which have 

 totally disappeared from other regions, although, as we 

 know from their fossil remains, they were once widely 

 spread over the globe. Thus, Hippopotamuses (or shall 

 we say Hippopotami ?) once ranged over the greater 



