RHINOCEROS 



XXX. 5 KllllNULLKUS 729 



counterbalances the body weight. The hind-legs provide the main 

 locomotor thrust. It is characteristic of this 'single-girder' type of back- 

 bone that the ilia are wide and vertically placed. The feet are basically 

 similar in all these groups in that several digits (usually three in the 



Fig. 484. Belozo: Skeleton of the Indian rhinoceros. (From Owen.) Above: Skull and 

 teeth of a young Indian rhinoceros. The grinding surface is made up of four milk pre- 

 molars and one adult molar on each jaw. The remaining permanent teeth have not erupted. 

 /. frontal;/, jugal; na. nasal; pa. parietal; sq. squamosal. (After Reynolds, The Vertebrate 



Skeleton, Cambridge.) 



rhinoceros) are preserved, making supports of large area. The brain of 

 the rhinoceros is small and the chief receptors are those of smell and 

 hearing; the eyes are mainly used in weak light. Like the tapirs they 

 are essentially timid animals, mainly nocturnal, though defending 

 themselves with a charge if attacked. They live singly or in pairs. 



The earliest members of the rhinoceros group, such as *Hyrachyus 

 of the Eocene, were very like other primitive perissodactyls, mostly 



