124 THE DESCENT OF MAN. Part I. 



grow into two distinct uteri, each with a well-constructed 

 orifice and passage, and each furnished with numerous 

 muscles, nerves, glands and vessels, if they had not 

 formerly passed through a similar course of develop- 

 ment, as in the case of existing marsupials. No one will 

 pretend that so perfect a structure as the abnormal 

 double uterus in woman could be the result of mere 

 chance. But the principle of reversion, by which long- 

 lost dormant structures are called back into existence, 

 might serve as the guide for the full development of 

 the organ, even after the lapse of an enormous interval 

 of time. 



Professor Canestrini, 36 after discussing the foregoing 

 and various analogous cases, arrives at the same con- 

 clusion as that just given. He adduces, as another 

 instance, the malar bone, which, in some of the Quad- 

 rumana and other mammals, normally consists of two 

 portions. This is its condition in the two-months-old 

 human foetus ; and thus it sometimes remains, through 

 arrested development, in man when adult, more especially 

 in the lower prognathous races. Hence Canestrini con- 

 cludes that some ancient progenitor of man must have 

 possessed this bone normally divided into two portions, 

 which subsequently became fused together. In man 

 the frontal bone consists of a single piece, but in the 

 embryo and in children, and in almost all the lower 

 mammals, it consists of two pieces separated by a dis- 

 tinct suture. This suture occasionally persists, more 

 or less distinctly, in man after maturity, and more fre- 



36 'Armuario della Soc. dei Naturalisti in Modena,' 1867, p. 83. 

 Prof. Canestrini gives extracts on this subject from various authorities. 

 Laurillard remarks, that as he has found a complete similarity in the 

 form, proportions, and connexion of the two malar bones in several 

 human subjects and in certain apes, he cannot consider this disposition 

 of the parts as simply accidental. 



