58 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



author would link them by relying almost entirely 

 on a single characteristic, that of a double occipital 

 condyle opposed to the single occipital condyle of the 

 Reptiles and Birds. The recent tendencies of palae- 

 ontologists who rather lean towards the Anomodont 

 Reptile group as the origin of the Mammals are totally 

 contrary to this purely theoretical view which at 

 the present day no longer seems to have a single 

 champion. 



On arriving at the Mammals, Haeckel finds him- 

 self, in appearance at least, on more solid ground, 

 that is to say, in possession of more extensive 

 geological evidence. Few palaeontologists, no doubt, 

 will refuse to admit that the primitive Mammals 

 must have passed through the Monotrematic and 

 Marsupial stages before reaching the Placental. 

 This idea is in accord with the fact that all the 

 known Mammals of Secondary times seem really 

 to belong to these two first groups, but it must 

 be acknowledged that notwithstanding all that 

 may have been written on the sybmarsupial charac- 

 ters of the Carnivorous Creodonts of the lower 

 Tertiary, the intermediate types between Marsupials 

 and Placentals, or, if preferred, the primitive types 

 of the Placentals, are still quite unknown to us. 



At the base of the placental ancestors of man, 

 Haeckel places the Prosimian or Lemur stage. 

 This idea does not lack probability, for we are, in 

 fact, acquainted with the lower Primates from the 

 earliest Tertiary of America and Europe. But how 

 far did these ancient Primates resemble the Lemurs ? 

 This is a point which is far from being settled. We 

 are still less agreed with regard to the passage, 



