THE SKELETON 79 
In the great majority of Reptiles a similar aperture (ect- 
epicondylar foramen) is found on the outer side of the humerus, 
(Fig. 55, A ii), and in some both foramina are present. These 
are in both cases nerve canals, which fact suggests that they may 
not have arisen either among Amphibians or Reptiles, but rather 
among animal forms phylogenetically still older. 
[In consideration of the facts already recapitulated (pp. 68-70) con- 
cerning the comparative anatomy and development of the vertebrate limb- 
skeleton, the probability that these condylar foramina may be indicative of 
a] polymeric origin of the basal segments of the limb-skeleton must not be 
overlooked, for, in the Ontogeny of the Sharks and Sturgeons, these latter can 
be traced to an origin by concrescence from parallel cartilaginous rays. If this 
be the meaning of the foramina, the fact that among living Reptiles they are 
most marked in the most primitive genus (Hatteria) is the more interesting. 
I have elsewhere! raised the question whether the foramina nutritia, 
occurring in the long bones of the hmbs, may not have had a similar origin. 
A wide field is here open for research, in which paleontology should play an 
important part. 
Special interest attaches to the skeleton of the human hand, 
and there is still abundant room for 
further investigation concerning it. 
Taking first the carpus, the re- 
semblance of that of Man to the 
carpus and tarsus of the tailed Am- 
phibians is most striking. In its 
proximal row there are the three well- 
known bones, the radiale (scaphoid = 
tibiale in the pes), the intermedium 
(lunar), and the ulnare (cuneiform = 
fibulare in the pes), cf. Figs. 56, 57, 
59, 60. In the distal row, counting 
from the inner or radial face, lie the 
first carpale (trapezium = Ist tarsal or 
: : Fig. 56.--SKELETON OF THE HIND- 
ento-cuneiform in the pes); the 2nd car- [ays or a Taep AMPHIBIAN 
pale (trapezoid = 2nd tarsale or meso- Pere aes eae Belch 
cuneiform in the pes); the 3rd carpale % intermedium; f, fibulare ; 
(magnum = 3rd tarsale or ecto-cunei- Hees Pe SE ea 
form in the pes); and the 4th carpale 
of the skeleton (cf. Rep. Internat. Medic. Congress, Lond. 1881). A remarkable 
outcome of the latter tendency has been recently described by Griinbaum, in the 
discovery of a ligament which, bridging over the posterior condylar foramen, forms a 
tunnel for a branch of the occipital artery, and, by ossification, may form ‘‘a ring of 
bone projecting downwards from the lower surface of the occiput” (Jowr. Anat. and 
Phys., vol. xxv. p. 428, and Macalister, iiid. p. di.).] 
1 Das Gliedmassen Skelet (see ante, p. 74, footnote). 
