1892.] The Contemporary Evolution oj Man. 469 



increased rotation) ascends from 152° in the polished stone 

 age to 164° in the modern European. The intercondylar for- 

 amen or perforation of the olecranon fossa is exceptionally 

 well recorded; 1 it is found in thirty per cent, of skeletons of 

 the reindeer period ; in the dolmen period it fell to twenty- 

 four per cent.; in Parisian cemeteries between the fourth and 

 tenth centuries it is found in 5.5 per cent. ; it has now fallen 

 to 3.5 per cent. The condylar foramen, occasionally forming 

 a complete bridge of bone above the inner condyle and trans- 

 mitting the median nerve and brachial artery, is known as 

 the " entepicondylar " foramen in comparative anatomy, and 

 is one of the most ancient characters of the mammalia: it 

 reverts palseogenetically in one per cent, of recent skeletons, 

 but much more frequently in inferior races (Lamb). In the 

 wrist-bone is sometimes developed another extremely old 

 structure— the os centrale. Gruber 2 reported it- re* 

 .25 per cent, approximately. This is a case of neogenetic 

 reversion, for Leboucq 3 shows that there is a distinct centrale 

 in every human carpus in the first part of the second month, 

 which normally fuses with the scaphoid by the middle of the 

 third month. . . 



The divergence of the female from the male pelvis is an 

 important feature of our progressive development; it is proved 

 by the fact that as we descend among the lower races it 

 becomes increasingly difficult to distinguish the female skele- 

 ton from the male, for the pelves of the two >exv^ are nearly 

 uniform. Here it seems to me is a most interesting pro .hi 

 for investigation. Arbuthnot Lane'-'' view- ol the m 

 causes of this divergence, which are - 

 may be weighed with the theory of survival ot the htte.-t. <>i 

 a large female pelvis is perhaps the best example that can he 

 adduced of a skeletal variation which would be preservi d by 

 natural selection for reasons which are self-evident. The third 

 trochanter of the femur is believed by Professor D wight, of 



Virchow's A v 1835, p. 353. 



