434 Savage and Wyman, External Characters, 
strength of these suspensory muscles of the body, and which 
are so essential to an arboreal life. The humerus is slightly 
twisted, though less so than in man, but there is not the prom- 
inence of bone corresponding with the insertion of the deltoides, 
its anterior face being uniformly concave, and the posterior 
convex, as in the Chimpanzée. The smaller head is less 
spherical, the trochlear portion less deeply emarginated, and the 
internal edge of the trochlea less prominent than in the 
T. niger, but as in the latter, the humerus has a perforation 
of its inferior extremity. 
In the proportions between the length of the humerus and 
ulna, the Engé-ena recedes less from the human type than 
the Orang or the Chimpanzée. In S. satyrus the ulna 1s 
nearly an inch longer than the humerus, in T. niger the two 
bones are (as in Mr. Owen's specimen’ ) nearly equal ; in the 
Engé-ena the ulna is to the humerus as 1 to 1.2, and in man 
as 1 to 1.5 very nearly. (See table.) "The radius more stout 
and massive than in the Chimpanzée, has the same curved 
. form necessary for that constantly pronated condition of the 
hand essential to their climbing habits. 
The sacrum was broken through the body of the fifth ver- 
tebra; the canal was complete as far as the broken edge; and 
the intervertebral spaces, except the first, had become oblitera- 
ted. As in the Chimpanzée compared with that of man; the 
sacrum was long and narrow, and its anterior face more nearly 
straight than in either. The articulating surface {facet 
articulaire) extends down on each side as far asa point m th 
way between the third and fourth sacral foramina, its breadt 
as in the Chimpanzée, being proportionally much less than in 
man ; the broadest part is at the lowest extremity, om 
very narrow above; in man the surface is much broader, LI 
the breadth more nearly uniform throughout. Here agam; ia 4 
have a mark of the inferiority of the higher Quadruman?; > "He 
3 Op. Cit. p. 375. In a skeleton presented to the Boston Society of Nal : 
. History by Dr. Savage, the ulna is 0.8 inch shorter than the humerus. 
