CLASS MAMMALS. 



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Examples: Opossum, kangaroo, Tasmanian wolf, bandi- 

 coots. 

 Young retained in uterus until developed, 



Sub-class Placentalia. 



Teeth wanting or without enamel Order Edentata. 



Examples: Sloth, armadillo, scaly ant-eater. 

 Teeth with enamel (wanting in most Cetacea) . 



Hind limbs wanting; digits not distinct. .Order Cetacea. 



Examples: Whales, dolphins, porpoises. 

 Hind limbs present; digits distinct. 

 Digits with claws. 



Front limbs modified to form wings, 



Order Cheiroptera. 

 Examples : Bats. 

 No wings. 



Canine teeth wanting; incisors large and sharp, 



Order Rodentia. 



Examples: Rats, mice, beavers, squirrels, rab- 

 bits, gophers. 

 Canines and incisors present, small and sharp, 



Order Insectivora. 

 Examples: Moles, and shrews. 

 Canines large and suited to tearing flesh, 



Order Carnivora. 



Examples: Seals; walruses; cats, dogs, bear, 

 etc. 

 Digits with hoofs ; molar teeth suited to grinding, 



Order Ungulata. 

 Toes 5; incisors forming "tusks; nose a long flexible 



proboscis Sub-order Proboscidea. 



Examples: Elephants; mammoth and mastodon 

 (extinct) . 

 Toes less than 5. 



Odd number Sub-order Perissodactyla. 



Only one toe on each foot (others mere splints), 



Horse family. 

 Examples: Horse, ass, zebra, quagga, mule. 



Three toes Tapir and Rhinoceros. 



Even number Sub-order Artiodactyla. 



Chew the cud; upper front teeth wanting, 



Ruminants. 



Examples: Camels, oxen, bison, sheep, ante- 

 lopes. 



