ANATOMICAL STRUCTURE OF ANTHROPOID APES. 67 



of a circle. There is, for the most part, only one 

 small superior iliac spine, and the ischii are some- 

 what turned outwards, and furnished with broad, 

 rounded tuberosities, and for the most part with only 

 a single large sacro-sciatic notch. The horizontal 

 rami of the pubes are narrow, while the descending 

 rami are wide. The os sacrum is narrow, and shaped 

 like a protracted cone, turning abruptly outwards, 

 and resembling the basal joint of a true tail. The 

 coccyx appears to be the rudiment of a genuine tail. 



The bones of the shoulder-girdle present interest- 

 ing peculiarities. The clavicles are long and slender, 

 with a leaf-shaped, flattened end articulating with 

 the scapula, and a thickened end articulating with 

 the sternum. The scapula is a very large triangular 

 bone, resembling the human scapula in its general 

 form, and the supra- and infra-spinous fossae are not 

 strongly marked. The long and powerful humerus 

 has its head inclined at an angle of sixty degrees 

 towards the axis of the shoulder. Frequently, but 

 not invariably, the lower, flattened extremity of the 

 humerus is pierced on one or both sides above its 

 rounded eminence, and this is termed by Darwin 

 the intercondyloid foramen. 



The radius has a powerful head, and a shaft con- 

 siderably curved outwards while it is, on the other 

 hand, curved backwards and inwards at the elbow. 

 The bones of the carpus, metacarpus, and phalanges 

 are remarkably long, broad, and deep. The develop- 

 ment of the femur corresponds to that of the whole 

 skeleton. Its middle piece or shaft is curved in 

 front and flattened behind. The shaft of the tibia 



