788 MAMMALIAN ANATOMY 



The scaphoid can be easily recognized by its characteristic form. 

 Its concave proximal surface articulates with the astragalus ; its convex 

 distal surface, by the three triangular facets, joins the three cuneiform 

 bones. In some specimens the outer surface articulates with the 

 cuboid. 



The entocuneiform is the largest of the three. In form it is 

 almost quadrate, but greatly flattened. The proximal surface artic- 

 ulates with the scaphoid, the distal surface with the first metatarsal, 

 and the outer surface with the mesocuneiforin and the second meta- 

 tarsal. Its plantar surface presents a blunt tuberosity. 



The mesocuneiform is somewhat prismatic, the narrow side on the 

 sole of the foot. The bone articulates with the scaphoid, the second 

 metatarsal, and the other two cuneiforms. 



The ectocuneiform is relatively much smaller than in the cat, and 

 lacks the long plantar hook. By its four surfaces it articulates with 

 the scaphoid; the cuboid and the fourth metatarsal; the mesocuneiform 

 and the second metatarsal ; and the third metatarsal. 



The cuboid articulates by its proximal surface with the calcaneum, 

 by its inner surface with the scaphoid and ectocuneiform but not with 

 the fourth metatarsal, and by its distal surface with the fourth and 

 fifth metatarsals. 



The first metatarsal is shorter and more strongly developed than 

 the others, which are comparatively slender and decrease in size from 

 within outward. Their bases are less complex than in the cat. Sesa- 

 moid bones are developed only on the great toe. 



The phalanges of the foot resemble the phalanges of the hand, 

 but, with the exception of those of the great toe, they are less de- 

 veloped. The shafts of the proximal phalanges are very narrow ; the 

 shafts of the middle and distal phalanges are broad, and are distin- 

 guishable only as slight transverse constrictions of the bone. 



THE NUTRIENT CANAL AND THE GEOWTH OF BONES. 



On page 38, in referring briefly to the relative growth of the parts 

 of bones, mention was made of the fact that the shaft of a long bone 

 unites first with that epiphyseal end toward which the canal for the 

 nutrient artery is directed. The student must not suppose, however, 

 that this fact can explain all the problems which arise in the study of 

 relative growth; other facts must be settled before the subject can be 



