ANATOMICAL STRUCTURE OF ANTHROPOID APES. 135 



Rosenberg has lately given an incontestable prooi 

 of the presence of this bone in the human embryo. 

 It is generally absorbed again, but sometimes it 

 persists, and may be found in an adult as a well- 

 formed ninth carpal bone. Cases of the persistence 

 of the OS centrale in man have been chiefly collected 

 and published by the diligence of the Russian 

 anatomist, Gruber. It is now suggested that there 

 may also be indications of os centrale in the carpus 

 of embryos of the gorilla and chimpanzee, but up 

 to this time materials for such researches have been 

 wanting. 



I cannot accept the theory that os centrale carpi 

 is merely a detached portion of the scaphoid bone. 

 In a very young chimpanzee this bone is undoubtedly 

 superficially indented with two transverse furrows, 

 but the three segments display only one uniform 

 development of bone. The distinct formation of os 

 centrale, and its occasional appearance in man, testify 

 that it has an independent existence. Rosenberg 

 holds that this bone is not merely the os centrale of 

 mammals, but that it is homologous with the two 

 ossa centralia of the fossil Enaliosauria. It has 

 become abortive in proportion to the reduction in 

 size which has taken place.* There would be no 

 great difficulty in tracing back this bone to remote 

 types of vertebrate animals, even as far as the 

 Urodela (Wiedersheim) of Eastern Asia.f The per- 

 sistence of this bone in man must be regarded as 

 a reversion, not as an arrest, of development. 



* Hartmann in Archiv. filr Anatomie, etc., by Reichert and Du 

 Bois-Reymond, pp. 639-643 : 1876, 



t Wiedersheim, Morphologisches Jahrhuch, ii. 421. 



