The Mammals of New Jersey. 



Mammals, the majority of which are more popularly known 

 as quadrupeds, form the highest class of Vertebrate or "back- 

 boned" animals.. 



Most of them are four-footed and covered with hair, and are 

 terrestrial in their habits, such as the dog, the horse and the 

 mouse, but two groups that belong to the mammalia differ ma- 

 terially from the rest, both in external appearance and in habit. 



The bats, while looking not unlike mice so far as their head 

 and body are concerned, have their hands modified into mem- 

 branous Avings which are carried down the sides of the body so 

 as to include the hind legs and tail, thus, admirably fitting these 

 little animals for their aerial life. 



The whales and dolphins, on the other hand, are fitted for a 

 life in the ocean. They are practically hairless, with no trace 

 of hind limbs, the fore limbs modified into flippers, the tail broad 

 and flat like that of a fish, only that it is transverse instead oi 

 vertical. These beasts look little like the hairy quadrupeds of 

 the land, and it is not surprising that in the popular mind they 

 are associated with the fish. As a matter of fact their skeletal 

 structure is like that of the quadrupeds, while they have warm 

 blood and suckle their yoimg, all of which are essential charac- 

 teristics of the class of mammals. The existing mammals fall 

 into three groups : 



(i) The Protothcria, curious remnants of an earlier fauna, 

 now only represented by the Duckbill and Spiny Anteater of 

 Australia, mammals with horny bills like birds and which lay eggs 

 somewhat like those of certain reptiles. 



(2) The Marsupialia or pouched mammals also an ancient 

 group represented by the Kangaroos and other Australian mam- 

 mals and by the opossums of North and South America. 



(37) 



