ITS NEAREST EXISTING RELATIONS. 57 



premaxillae, from which they are separated by a 

 deep and wide fissure; the latter bones are very 

 small, generally not meeting in the middle line in 

 front, often quite rudimentary, a specialization con- 

 current with the loss of the upper incisor teeth. The 

 brain cavity is very small for the size of the skull. 

 Vertebrae Cervical, 7; dorsal, 19-20; lumbar, 3; 

 sacral, 4 ; caudal, about 22. 



The RMnocerotidce are all animals of large size, 

 but of little intelligence, generally timid of disposi- 

 tion, though ferocious when attacked and brought 

 to bay, using the nasal horns as weapons, with which 

 they strike and toss their assailants. Their sight is 

 dull, but their hearing and scent are remarkably 

 acute. They feed on herbage, shrubs, and leaves 

 of trees, and, like so many large animals which in- 

 habit hot countries, sleep the greater part of the day, 

 being most active in the cool of the evening or even 

 during the night. They are fond of bathing or wal- 

 lowing in the mud. None of the species have been 

 domesticated. The family once contained many 

 more species and was much more widely distributed 

 than at present. As already indicated, our knowl- 

 edge of them is as yet but f ragmentary, though con- 

 stantly augmenting, especially by discoveries made 

 in the Tertiary deposits of North America, a region 

 from which they all died out long ago, though, J 



