128 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



yy. Feet diplarthrous. 



Limbs ambulatory; a postglenoid process ; molars qua- 



dritubercular ; lo. Aticyhpoda. 



/?/?/?. Anterior limbs with flexible joints and distinct digits ; 



ungual phalanges not compressed and acute at apex^ (Un- 



gulata^). 



e. Tarsal bones in linear series; carpals generally in linear 



series. 



Limbs ambulatory; teeth with enamel : ii. Taxeopoda.^ 

 ee. Carpal series alternating ; tarsal series linear. 



Limbs ambulatory ; median digits longest ; teeth with 

 enamel : 12. Toxodontia. 



t£E. Tarsal series alternating ; carpals linear. 



Cuboid bone partly supporting navicular, not in contact 

 with astragalus : 13. Proboscidia. 



eeee. Both tarsal and carpal series more or less alternating. 

 Os magnum not supporting scaphoides ; cuboid sup- 

 porting astragalus ; superior molars tritubercular : 



14. Amblypoda. 



Os magnum supporting scaphoides ; superior molars 



quadritubercular : * 15. Diplarthra.^ 



1 Except the Hapalidas. 



2 Lamarck, Zoologie Philosophique, 1809. 



3 This order has the following suborders : 



Carpal series linear ; no intermedium; tibia not interlocking with astraga- 

 lus ; no anapophyses ; incisors rooted ; hallux not opposable : 



Condyla rth ra . 



Carpal series linear; an intermedium; tibia interlocking with astragalus; 

 hallux not opposable : Hyracoidea. 



An iniermedium ; fibula not interlocking; anapophyses; hallux opposable; 

 incisors growing from persistent pulps : Daubejitotiioidea. 



An intermedium; fibula not interlocking; anapophyses; hallux opposable; 

 incisors rooted ; carpus generally linear : Quadrumatia. 



No intermedium ; 6 nor anapophyses; carpal rows alternating; incisors 

 rooted : Anthropomorpha.l 



The only difference between the Taxeopoda and the Bunotheria is in the 



unguliform terminal phalanges of the former as compared with the clawed or 



unguiculate form in the latter. The marmosets among the former division 



are, however, furnished with typical claws. 



4 Except Trigonolestes. 



fiThis order includes the suborders Perissodactyla and Artiodactyla. It 

 is the Ungulata of some authors. 



6 Except in Simla and Hylobates. 



7 Includes the Anthropoid apes and man. 



