546 ANATOMY OF VERTEBRATES. 



or ulnar di\asion of the great sigmoid cavity is less developed than 

 in the Orang, and its margin is more extensively interrupted at 

 its middle part : the radial division of the same cavity extends 

 more nearly to the back part of tlie olecranon. The lesser sigmoid 

 ca^dty is more nearly semicircular than in the Orang. The ridge 

 continued a short way do^wnward from the inner and ulnar angle 

 of the great sigmoid cavity is sharply defined, but the fossa which 

 it bounds is much less deep than in the Orang. The interosseous 

 ridge is not marked, the bone being there rounded off in the 

 Chimpanzee. The styloid process is better developed than in the 

 Orang. The carpus consists of eight bones, as in Man. The 

 thumb, 1, is relatively longer and stronger than in the Orang. 

 The pelvis is longer in proportion to its breadth than in the 

 Orang. The tuberosities of the ischia are expanded, flattened, 

 and bent outward, as in the Orang. The expanded part of the 

 ilium, 62, is slightly concave anteriorly, but in the Orang it is 

 plane. The spine of the ischium is parallel transversely with the 

 middle of the obturator foramen, but in the Orang it is parallel 

 ^vith the upper border of that foramen. The ilio-ischial angle is 

 165°. The ischio-pubic symphysis is longer than in the Orang : 

 but retains its longitudinal parallelism with the sacro-lumbar 

 series of vertebra?. The posterior wall of the acetabulum is still 

 the deepest. The bones of the hind extremity are relatively 

 longer and stronger, especially the femur, than in the Orang ; but 

 the most marked distinction between the two great anthropoid 

 Apes is seen in the length and strength of the hallux, i, in the 

 Chimpanzee. The articulation of the tarsus A\dth the leg still, 

 however, favours the oblique position of the foot, and adapts it 

 for grasping. The femur, 65, shows the pit upon its head for the 

 ligamentum teres : both trochanters are relatively larger than in 

 the Orang : the neck is longer, thicker in proportion to the head, 

 and passes oif at a less obtuse angle with the shaft. The shaft 

 is slightly bent forward ; it is not straight : the condyles are more 

 expanded, especially the inner one. 



In the Gorilla, fig. 346, the scapula is broader than in the 

 Chimpanzee, but difi^ers from that of Man in the more oblique 

 course of the spine, wliich gives greater extent to the superior 

 costa ; in the greater length and breadth of the coracoid, 52 ; in 

 the straightness of the inferior costa ; and in the greater con- 

 vexity of the base, especially as it approaches the lower angle : 

 the plane of the glenoid cavity is less parallel with the base than 

 in Man, it looks more obliquely upward ; the suprascapular notch 

 is not defined. 



