mammalia 



47 1 



Among the other groups of Eutheria are : the Rodentia, to 

 which belong rabbits, rats, mice, squirrels, etc., 

 all characterised by two pairs of large incisors 

 adapted for gnawing and by the absence of canines ; the 

 Insectivora, to which belong moles, hedgehogs, and 

 shrews, with sharp ; cusped teeth and a long snout ; the 

 Chiroptera or bats, in which the fore-limb becomes a 

 wing by the lengthening of its digits and the formation of 

 a web of skin between them and the side of the body ; and 



Fig. 350. — The Coccyx, or vestige of the caudal vertebra- 

 of man. — From Cunningham. 



1, 2, Transverse processes ; j, fur sacrum ; 4, cornu. 



the Carnivora, to which belong dogs, cats, bears, and seals. 

 These latter are generally bold, intelligent animals. They 

 have claws, which in the cats are retractile. The canines 

 are strong and sharp, and some of the back teeth are 

 adapted by their narrow, blade-like crowns for cutting 

 flesh. These are the four upper premolar and the first 



lower molar. The dental formula of the dog is ■ ' ' -- — . 



3> 1, 4, 3 

 Dogs and cats are digitigrade, and, like most of the other 

 Carnivora, have five fingers and four toes. The clavicles 

 are rudimentary. 



The last group of mammals which we shall mention is 



