394 



CLASSIFICATION OF VERTEBRA7ES. 



which intergrade between these, largely obliterating the distinctions. In no 

 group of mammals have the lines of descent been worked out more com- 

 pletely than here. 



FIG. 365. A, right fore foot of horse, from Huxley, i, radius ; 3, scaphoid ; 



4, lunare ; 5, cuneiforme ; 6, pisiforme ; 7, magnum; 8, unciforme; 9, meta- 

 carpal III ; 10, splint bone (metacarpal IV) ; 1 1, 14, sesamoid bones ; 12, proximal 

 phalanx (fetter bone); 13, middle phalanx (coronary bone) ; 15, distal phalanx 

 (coffin bone). B, left hind foot, i, tibia ; 2, calcaneum ; 3, astragalus ; 4, cuboid ; 



5, navicular or scaphoid ; 6, ectocuneiforme ; 7, metatarsal Til (cannon bone) ; 8, 

 metatarsal IV (splint bone) ; 9, u, 12, phalanges (see fig. A) ; 10, 14, sesamoids. 



