THE MAMMALIA. 41 



an inhabitant of Britain, and lived to be the contemporary of man. 

 Quite recently, one of these enormous animals has been suddenly 

 revealed in his " habit as he lived." Part of a river cliff, in 

 Siberia, was broken away by a thaw, and there stood a perfect 

 woolly rhinoceros, perfect in hide and hair, as in life. An 

 admirable illustration of the animal appeared in "St. Nicholas" 

 for March of last year. Its life, as a species, was remarkably 

 short. It is " essentially a Post-glacial Mammal, and is mainly 

 found in quaternary cave-deposits and river gravels " (Nicholson). 



Our modern rhinoceroses are therefore amongst the most 

 ancient " survivals " among Mammals, and have diminished very 

 Httle in size, though wofully in number of species, there being 

 only one living genus. The extinct families of Perissodactyls 

 were mostly clumsy animals of low specialisation and undeveloped 

 brain. In Coryphodon of the Eocene, " casts of the brain-case 

 indicate that the cerebellum was large, the cerebral hemispheres 

 much reduced in size, and the olfactory lobes large, and entirely 

 in advance of the hemispheres," and the " dentition was com- 

 plete," — an infallible sign of low development. Each of the five 

 horny toes, also, was functionally complete. The extinct 

 Brontotheridce, from the Miocene of North America, had brains 

 as low in type as that of Coryphodon. Their feet and teeth were 

 rather more specialised, and they had two large horn-cores upon 

 the maxillary bones. 



The Palaothei'idce show affinities with both the tapir and the 

 horse, and probably included amongst their number the ancestors 

 of these latter animals. Macrauchenia had affinities with both 

 the camel and the horse. In short, in Eocene and Miocene 

 times, whilst orders were more or less clearly marked out, species 

 were still in wild confusion, and everything appears to have 

 affinities with everything else. 



Amongst the Artiodactyls, or pair-hoofed Ungulates, we have 

 a most curious surviving example in the hippopotamus, of the 

 primary type from the Eocene. The " Eocene animals, with 

 tuberculate teeth, and likewise the Early Tertiary ancestors of the 

 ruminants, with crescentic teeth, had to dwell principally in waters 

 and marshy ground. Their descendants, for the most part, 

 adapted themselves gradually to life on dry ground, and this is 



