77//; MAMMALS. 





The robin is our most common bird; it begi 

 ire the lea^ .'pen-; n pair will build thi 



terior of their nest in two or three days, but the linii 

 Dpi finished until after the 13 is laid: hence it is about 



•i week before the nest 1 and the first lid. 



Class VIII. — Mammalia (Rat, Dog, MonJce t . Man). 



General Characters of Mammals.— In this the hig 

 ciass of vertebrates hair takes the plac< i -. and the 



young are nourished with milk. 

 Mammals walk on all fours, man 



,L r the only truly upright 

 mammal, walking firmly on his 

 hinder limbs, and using h 

 limbs as arm- for grasping and 

 performing all those actions 

 which minister t<> his intellectual 

 wants. 



A- nd in the mamma- 



lian series, the limbs, particu- 

 larly the fore limbs, arc vari- 

 ously modified. The limbs of 

 whales are 'paddle-like, though "I - !~ 

 the bones of the limbs are identi- 

 cal with those of other mammal-. 

 The tect of the seal are webbi 



forming flippers; it cannot >u\>- \ ,, K . 



port itself on its limbs, but the u,umb,e8S Mo ' 

 t'.>re-t*eet have considerable freedom of motion. In thedog 

 the fore-limbs have but little motion of the radius on the 

 ulmi. hut the eats have more of this rotary motion, enabling 

 them to grasp with the fore This rotary motiou of 



the fore-arm, the fore-foot becoming a hand, . in the 



thumbless monke; £. 280), and in those pr< with 



a thumb, in the gorilla, and especially in man. r J 



!ie of specialisation of all four liml q in the h 



