THE RECESSION OF THE SNOUT REGION 85 



(Dipodinoe), and many other hopping Rodents, eat food 

 held between their fore-paws. Beavers can hold a small 

 object clasped by the palm and claws of one hand, and 

 Marmots (Arctomys) even go farther than this, for when 

 sitting erect they can pick up their food from the ground. 

 Truly arboreal animals of other stocks again possess this 

 power, and squirrels, phalangers, and opossums are good 

 examples of limited hand-feeding arboreal types. So 

 far as the process goes in any of these animals, the changes 

 which we are picturing in the Primate stock take place 

 harmoniously. 



A typical Primate obtains its food with its hand instead 

 of adopting the common mammalian method of taking 

 it with its mouth: one function of the mouth, that of 

 food-getting, is therefore relegated to the hand in the 

 Primates. 



It may be said on broad lines that throughout the 

 whole of the animal kingdom the mouth parts show a 

 development depending upon the nature of the animal's 

 food and the method of taking it. If it is the hand 

 which becomes the grasping organ, the mouth and the 

 anatomical structures connected with it need no longer 

 be developed in any special way to carry on this function. 

 The food-grasping power of the Primate hand renders 

 unnecessary the development of grasping lips and a long 

 series of grasping teeth. Again, the fact that the food 

 once grasped by the hand is conveyed by the hand to the 

 mouth renders the mouth and its associated parts merely 

 an organ for dealing with food already grasped and carried 

 to it. A mouth merely adapted for the reception of food 

 already grasped and brought to it is a structure very 

 different from a mouth adapted for the purposes of reach- 

 ing out for food, seizing the food so reached, and subse- 

 quently dealing with it. 



When the mouth is the food-obtaining organ, there is a 

 necessity for its situation being advanced from the face, 

 and especially that part of the face in which the eyes are 



