38 The. Descent of Nan. Paut t 



bo whicli mau Moags, occasionally malce their appearance iu 

 him, though iiot found in the normal human embryo; or, ii 

 normally present in the human embryo, they become abnormally 

 developed, although in a manner which is normal in the lower 

 members of the group. These remarks will be rendered clearer 

 by the following illiihtrations. 



In various mammals the uterus graduates from a double 

 crsjan, with two distinct oriiioes and two passages, as in the 

 mtivsupials, into a single organ, which is in no way double, 

 except from having a slight internal fold, as in the higher apes 

 and man. The rodents exhibit a iserfect series of gi'adation.s 

 between these two extreme states. In all mammals the uterus 

 is developed from two simple primitive tubes, the inferior 

 portions of which form the coinua ; and it is, in the words of 

 Dr. Farre, " by the coalescence of the two eornua at their lower 

 " extremities that the body of the uterus is formed in man ; 

 " while in those animals in which no middle portion of body 

 " exists, the eornua remain un-united. As the development of 

 " the uterus proceeds, the two eornua become gradually shorter, 

 " until at length they are lost, or, as it were, absorbed into the 

 " body of the nterus.'' The angles of the uterus are still pro- 

 duced into eornua, even in animals as high up in the scale as the 

 lower apes and lemurs. 



Now in women, anomalous cases are not very inl'reqtient, in 

 which the mature utervis is furnished with eornua, oris partially 

 divided into two organs; and such cases, according to Owen, 

 repeat " the grade of ooncentrative development," attained by 

 certain rodents. Here perhaps we have an instance of a simple 

 arrest of embryonic development, with subsequent growth and 

 perfect functional development ; for either side of the partially 

 double uterus is capable of performing the proper ofBce of 

 gestation. In other and rarer ca-ses, two distinct uterine cavities 

 are formed, each having its proper orifice and passage.^' No 

 such stage is passed through during the ordinary development 

 of the embryo, and it is difficult to believe, though perhaps not 

 Impossible, that the two simple, minute, primitive tubes should 

 know how (if such an expression may be used) to grow into two 



there i/j any relation between the Anatomy and Riysiology,' vol t,, 



development of supernumerary di- 1869, p. 642. Owen, 'Anatomj 



gits and reversion to some lowly of Vertebrates,' vol. iii., 1868, p, 



organised progenitor of man. 687. Professor Turner in 'Edin 



2' See Dr. A. Farre's well-known burgh Medical Journal,' February, 



article in the ' Cj'clopaedia of 1865. 



