28 
THE DESCENT OP MAN. 
Part t 
In some of the Quadrumana, in the Lemuridse, and 
especially in the Carnivora, there is a passage near the 
lower end of the humerus, called the supra-condvloid 
foramen, through which the great nerve of the fore limb 
passes, and often the great artery. Now in the humerus 
ot man, as Dr. Struthers 37 and others have shewn, there 
is generally a trace of this passage, and it is sometimes 
fairly well developed, being formed by a depending 
hook-like process of bone, completed by a band of 
ligament. When present the great nerve invariably 
passes through it, and this clearly indicates that it is the 
homologue and rudiment of the supra-condyloid fora- 
men of the lower animals. Prof. Turner estimates, as 
he informs me, that it occurs in about one per cent ot 
recent skeletons. But this case does not possess much 
interest, as the foramen is not regularly present in 
the higher Quadrumana. It is therefore doubtful, as 
Mr. Busk has remarked to me, whether its occasional 
presence in man can be attributed to the retension or 
reversion ot a primordial structure. 
There is another foramen in the humerus, which may 
be called the inter-condyloid. This occurs in various 
anthiopoid and other apes , 38 but likewise in many of the 
towel animals, and occasionally in man. It is remarkable 
that this foramen seems to have been much more fre- 
quently present during ancient than during recent times. 
Mr. Busk 39 has collected the following evidence on this 
head : Prof. Broca “ noticed the perforation in four and a 
B. ii. s. 278), have both remarked on the singular fact of this rudiment 
sometimes causing death. 
37 ‘ The Lancet,’ Jan. 24, 18(13, p. 83. Dr. Knox, • Great Artists and 
Anatomists,, p. (13. See also an important memoir on this process by 
Dr. Grube, in the ‘ Bulletin de 1’Acad. Imp. de St. Petersbour^ ’ tom. 
xn, 1867, p. 448. D ’ 
38 Mr. St. George Mivart, ‘Transact. Phil. Soc.’ 1867, p. 310. 
39 “ On the Caves of Gibraltar,” * Transact. Intermit. Congress of 
Prehist. Arch.’ Third Session, 1869, p. 159. 
