MAMMALIA 



473 



the Primates, which include monkeys and man, together 

 Primates w '^ ^e lemurs, which link the monkeys to 

 other mammals. The Primates are plantigrade, 

 and either their thumb or their great toe — usually both — 

 can be opposed to the other digits so as to grasp objects. 

 There are well-developed clavicles, and the upper arm 

 and thigh are free, as in the elephants, not enclosed in 



Fig. 352. — The bones of the hard palate and upper permanent 

 teeth of man. 



a.p.J., Anterior palatine foramen, or foramen incisivum; tr., canine tooth; z'., 

 incisor teeth ; ?«., molar teeth; m.p.s., suture between maxillary and palatine 

 bones; p.p.f., posterior palatine foramen or foramen palatimtm majus ; pm. t 

 premolar teeth ; s.n.p., spina nasalis posterior. 



the skin of the trunk, as in most mammals. The orbits 

 are turned forwards, not, as is usual, to the sides, and, 

 except in the lemurs, are enclosed behind by a complete 

 bony wall. The majority of these peculiarities are con- 

 nected with an arboreal habit. It should be noted that in 

 most respects the Primates, and man with them, are not 

 highly specialised animals. In their limbs, in their teeth, 

 in the possession of clavicles, and in the alimentary canal 



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