214 VERTEBRATES 



ula over the end of the humerus). Other bones beginning 

 with the shoulder are the humerus, the radius, the smaller ; 

 and the ulna, the larger ; below the elbow, the carpal, wrist 

 bones; the metacarpal, or palm bones; and the phalanges, 

 or toes. Study and describe the articulation in each of 

 these bones. Make a diagrammatic drawing of front limb. 

 Compare with wing of bird. 



(b) In the hind limb the bones are equally easy to dis- 

 tinguish. Beginning with the pelvic girdle, find the femur, 

 with its deep ball and socket joint; the tibia and ftbula, be- 

 low the knee joint, which is covered with a patella or knee 

 cap ; the tarsus, the metatarsus and phalanges. Draw a dia- 

 gram of hind limb. Compare with leg of bird. 



Classification. — Adapted from Packard. — The rabbit belongs to 

 the family Leporidae, order Glires, and class Mammals. 



The class mammals contains the following orders which can be 

 fully worked out by reference to a larger Zoology. 



Orders of Mammals. 



Subclass I. With long toothless jaws like a duck's bill, young 

 carried in a mammary pouch Ornithodelphia. 



Order i. Monotremata. Duckbill. 



Subclass II. Young born alive, but kept for awhile in a pouch. 



Didelphia. 



Order 2. Marsupialia. Opossum. 



Subclass III. Young born of considerable size and perfect de- 

 velopment ; nourished before birth through a placenta ; brain 

 in most cases possessing convolutions Monodelphia. 



Order i. No incisor teeth ; sometimes entirely toothless. 



Bruta: Sloth. 



Order 2. Rodents; with large incisor teeth Glires: Rat. 



Order 3. Fore limbs often adapted for burrowing; teeth sharp; 

 feeding on insects Insectivora : Mole, 



Order 4. Fore limbs long, webbed, and adapted for flying. 



