IO6 Vertebrata. 



known of the bears are the polar or white beai of the 

 Arctic regions, the black bear of America, the brown 

 bear of Europe, and the grizzly bear of the Rocky 

 Mountains, possibly the same as the giant cave bear, 

 now extinct in these countries. The brown bear 

 formerly inhabited the British Islands, but was extir- 

 pated in Scotland in the eleventh century. 



The bears differ from the other carnivores in the 

 possession of tubercled teeth which can be used for 

 masticating vegetable matters, and many of them are 

 capable of partaking of a mixed diet. 



64. Order 10, Hyracoidea. A small order inclu- 

 ding a few little tail-less animals, natives of Africa and 

 Syria, one of which is the cony, mentioned in the 

 Bible. They are somewhat rabbit-like in habit, with 

 four toes on the fore feet, and three on the hinder, 

 each toe being armed with a flat nail. The molar 

 teeth have been compared in pattern to those of the 

 rhinoceros, and there are no canines. They have 

 sacculated stomachs and no collar-bones. 

 . 65. Order 11, Rodentia. Gnawing animals, the 

 largest order in the entire class, including the rats, mice, 

 squirrels, &c. They are all small and claw-bearing, 

 and have a most remarkable dentition. There is 

 usually but one incisor on each side of each jaw, and 

 this tooth is chisel-shaped ; it consists of two materials, 

 one a hard substance or enamel on the outside or 

 front, the other a softer dentine or bone-like substance 

 behind. In their growth the upper and lower teeth 

 oppose each other, and the constant friction during 

 feeding wears away the surface of the tooth, which 

 however is constantly growing, but as the soft dentine 



