22 PROFESSOR OWEN ON THE OSTEOLOGY OF 



tlie scaphoid, -which has a greater transverse extent and convexity : this, called in 

 Anthropotomy the 'head' of the astragalus, has relatively a shorter 'neck' in the 

 Gorilla, but more essentially differs by its direction obliquely inward, giving a corre- 

 s])onding aspect to the naviculare. 



The calcaneum answers to tlie combined cuneiform and pisiform bones of the carpus ; 

 it takes no share in joining the foot to the leg, but affords the chief lever to the great 

 flexor muscles of the foot. It is mainly distinguished in the Gorilla (PI. XI. fig. 2, 

 cl, & fig. 3) from that of Man {ib. fig. 1, cl) by the greater length and inner depth of 

 the posterior production or lever of the bone ; and the lower surface of the bone (fig. 3), 

 instead of being straight from before backward, broad and flattened from side to side, is 

 concave in the longitudinal direction, chiefly due to a terminal expansion of the heel- 

 bone, which bends downward and inward (tibiad) ; the l.ower surface is likewise convex 

 from side to side, and smooth except along the outer border. The outer articular 

 surface for the astragalus is divided by a deep and narrow groove from the outer side 

 of the bone, which it overhangs, and it is more convex from before backwards than in 

 Man ; the inner surface is more concave, broader and shorter. The breadth of the 

 articular part of the calcaneum is greater in the Gorilla than in Man. The calcaneum 

 in the Gorilla projects beyond the articular part, like a large lever-bone, — its terminal 

 expansion being supported on a subcylindrical constriction or neck, smooth, save along 

 the narrow tract on the lower and outer border {x,x, fig. 3), which shows a rough surface 

 like that on the broader under part of the Human calcaneum, indicative of a similar 

 application to the ground in moving along its surface. Whilst the chief modifications 

 in the Human calcaneum for habitual application of the heel to the ground for erect 

 posture are absent, the action of the gastrocneraial tendon upon the foot is favoured and 

 strengthened by the superior backward production and terminal expansion of the 

 calcaneum in the Gorilla. The cuboidal articulation is flatter and more vertical in 

 position than in Man. The groove for the passage of the flexor tendons beneath the 

 ' lesser process ' upon which they act in the raising of the heel with its superincumbent 

 weight upon the toes, is wider and more shallow in the Gorilla than in Man. 



The entocuneiform of the Gorilla (fig. 2, i) differs chiefly in the form and aspect of 

 the surface for the metatarsal of the hallux ; in Man (fig. 1 , i) this surface is nearly flat, 

 and forms or covers the fore part of the bone, presenting there a reniform figure ; in the 

 Gorilla the surface is convex transversely, curving from the fore to the inner side of the 

 bone, and forming almost the anterior half of that side. The outer (fibular) third of 

 the fore part of the entocuneiform is rough or non-articular, and encroaches by a notch 

 upon that border of the articular surface. The navicular surface is concave, and con- 

 tinuous with a narrow vertical tract for the entocuneiform. A second surface for the 

 same bone is afforded by the posterior facet of an articular surface on the upper and 

 outer part of the entocuneiform, the anterior facet of which articulates with the 

 base of the second metatarsal. 



