n 4 LIFE OF FLOWER 



set than the one functionally developed. This has been 

 got over by regarding these rudimentary germs as the 

 representatives of a prelacteal series. 



Passing on to another point, it has to be noticed that 

 exception has also been taken to Flower's view that the 

 replacing tooth of marsupials and its deciduous prede- 

 cessor correspond to the fourth, or last premolar of 

 placentals. The question has been discussed in con- 

 siderable detail in the Zoological Society's Proceedings 

 for 1899 by the present writer, who had for material 

 the dentition of certain extinct South American mammals 

 quite unknown to science at the time Flower's paper 

 was written. The result of these comparisons was to 

 render it evident, in the present writer's opinion, that 

 the replacing tooth of the marsupials corresponds to the 

 third, instead of to the fourth, premolar of placentals. 

 From this it follows that marsupials agree with 

 placentals in possessing only three pairs of true molars ; 

 the first of the four teeth in the former behind the 

 replacing tooth being the last milk-premolar (which is 

 never replaced) instead of, as supposed by Flower, the 

 first true molar. This conclusion, as pointed out by 

 the present writer in the paper referred to above, had 

 really been arrived at years previously by Owen, who 

 also believed the replacing tooth to correspond to the 

 third premolar of placentals. 



In thus bringing marsupials into line with placentals 

 as regards their dentition, this later interpretation 

 accords well with recent discoveries in regard to other 

 parts of the organisation of the former animals. It 

 should, however, be mentioned that the newer view is 

 by no means accepted by all zoologists, although it has 



