THE ORANG-UTANS. I73 



aged animal." ( IVaHace.) The supra-orbital ridges are pro- 

 minent, witliout being particularly so. The contour of the head 

 is more human in form, however, in j^outh than in age, when 

 the forehead is large and convex. The canine teeth are very 

 large and tusk-like in the male, but smaller in the female. The 

 upper molars exhibit on their crowns complex rugosities ; they 

 have four cusps and an oblique ridge, as in Man, from the 

 front inner, to the hind outer, cusp ; the lower molars are five- 

 cusped. The permanent canine teeth sometimes appear before 

 the last permanent molar has come into place. 



The thigh-bone {femur) has no round ligament binding its 

 articular head into its socket in the pelvis, a disposition which, 

 while it affords greater flexibility and freedom to the hind- 

 limbs in climbing, gives it much less firmness in walking on the 

 ground. The proportionate length of the foot to its limb is 

 greater in this genus than in any other of the Anthropoidea. 

 The ankle {tarsus) is very short, and the bones {phalatiges) of 

 the toes form the longest part of the foot. The great-toe is 

 especially short and divergent, its terminal bone being often 

 absent, while the bones of the digits are long and curved. On 

 account of the form of certain bones of the tarsus and their inter- 

 mobility the foot is set obliquely to the leg through the action 

 of one of its muscles (the tibialis ajiticus), so that the sole is 

 pulled to the inside when walking. The outer edge of the foot, 

 with the upper side of the fourth and fifth toes, is therefore 

 applied to the ground in the act of progression, while the 

 spread thumb supports most of the animal's weight. The 

 wrist {carpus) contains the complete number of nine bones, as 

 it possesses the os cciiirak wanting in Man and the Chim- 

 panzees. 



The breast-bone in the Orang is composed of ossifications 



