408 BIOLOGY. 



os pubis to the acromion, the marsupial bone to the 

 clavicle. 



Cephalic Members. 



2384. Both pairs of limbs are repeated in the head, 

 because in it the whole trunk is repeated; the upper 

 jaw corresponds to the arms, the lower jaw to the feet. 

 Each jaw consists of two members, which are ankylosed 

 in the higher animals at their point of meeting or in 

 front, but in Fishes are partly, and in Insects completely, 

 separated. 



2385. Each jaw consists of the same bony divisions 

 as the limbs of the trunk, of scapula, humerus, and fore- 

 arm ; or of pelvis, femur, and tibia. This is easily to be 

 demonstrated in Birds, Reptiles, and Fishes. 



2386. The digits are repeated in the teeth. The 

 teeth are claws. 



2387. There are therefore five kinds of teeth, which 

 correspond to the five digits. The thumb becomes the 

 canine tooth; the index-finger the carnivorous; the 

 middle finger the incisor, the ring-finger the premolar, 

 and the little finger the tuberculous molar tooth. 



2388. The intermaxillary with its incisor teeth belongs, 

 as well as the palatal bones, to the pharynx ; and is a 

 visceral or intestinal maxilla. 



2389. The lower animals therefore, as the Fishes, have 

 almost nothing but intermaxillary and palatal teeth. 

 They act principally upon the lingual teeth. The rep- 

 tiles have still palatal teeth, which higher up in the 

 vertebrate series disappear. 



Symmetry. 



2390. As the cervical ribs have nothing more to 

 inclose, have no longer to respire, but only to move ; 

 their symmetrical development is thus undelayed. The 

 symmetry is at first wholly attained by the act of open- 

 ing or apertion. 



2391. The limbs are the most symmetrical organs. 

 They are symmetrical in each smallest part, and these 



