INVERTEBRATE ZOOLOGY. 



53 



Order 2. Columbini. 



Order 3. Natatores. . 

 Order 4. Grallatores. 



Order 5. Scansores. 



Order 6. Passeres. 



Order T. Raptures. 



Class VI. Mammalia. 



Sul)-claSS I. MONOTREMATA. 



.Legs short, hind toe on a level with the 

 others. Edge of upper beak in contact 

 with that of lower. At base of upper 

 beak two outgrowths covering the nos- 

 trils. -^ Coluinba. 



.Aquatic birds with oily feathers and 

 short webbed feet. -^ Aitser, Lams. 



.Wading birds with very long slender 

 legs, and toes without webs. Often the 

 lower half of the tibia is free from feath- 

 ers. Neck and bill very long and slen- 

 der. -^ Grus, Scolopax. 



.Climbing birds. Inner forward toe re- 

 versible, giving the foot two toes in front 

 and two behind. Several groups of birds 

 belong here, not closely related. 

 ■jf Psittacus, Pious. 



.The most numerous group. Feet fitted 

 for perching. Two groups, the Oscines, 

 or singing birds, which have developed 

 a special organ, the Syrinx, at the fork- 

 ing of the bronchi : and the Clamatores, 

 without this. -^ Fthigilla, Cypselus. 



.Birds of prey. Toes furnished wath 

 hooked claws or talons. Point of upper 

 beak sharp and talon -like, projecting over 

 the lower one. ^ Aquila, Strix. 



. Warm-blooded vertebrates. Body clothed 

 with hair : young nourished ])y milk, a 

 secretion of integumental glands. Quad- 

 rate in middle ear. two occipital condyles. 



.Low oviparous mammalia with reptilian 

 characteristics. The young, immature 

 when hatched, are brooded either in a 

 nest or in a brood pouch temporarily de- 

 veloi)ed. No localized mammarj" glands; 



