38 COMPARATIVE ANATOMY 



subject, as frequently in men as in women. The accessory 

 mammae and teats are usually anterior (above) or posterior to (below) 

 the normal ones, and thus form with them two converging rows 

 from the axillary to the inguinal region, just as in many other 

 Mammals and in the human embryo, at a certain stage of which 

 four pairs of additional rudiments of mammary organs can always 

 be recognised. There is thus an indication of normal hyper- 

 mastism and hyperthelism in human ontogeny, which is paralleled 

 in those numerous mammals in which a " mammary ridge " or 

 "line" is formed, a structure which is probably comparable to the 

 " marsupial line " forming the rudiment of the pouch in Mar- 

 supials. 



In the male, the mammary apparatus becomes absorbed, 

 though frequently at birth and at puberty milk is produced in 

 the human subject. Male goats and castrated sheep have also 

 been known to give milk. 



