CHARLES DARWIN AND DARWINISM 41 



human branch. We shall see that the search for 

 the lower steps of the genealogy of man will show 

 themselves still more nebulous. 



Below the Apes Darwin goes to the group of 

 Pseudo-apes or Lemurs. For what reason ? Simply 

 because these animals are lower in the scale than the 

 true Apes, because they are geologically earlier, and 

 finally because they form a diversified group leading by 

 an insensible incline to the lowest placental mammals, 

 who are also the smallest and the least intelligent. 



Considerations similar to the preceding bring 

 Darwin down to the Marsupia, then to the Mono- 

 tremata, and through these latter to the Reptiles, 

 without our being able to discover in all this ex- 

 position any attempt, however rudimentary, to 

 state precisely the fossil genera through which this 

 lengthy genealogy must have passed. 



Coming still lower down in the scale of beings, 

 Darwin recognizes that the five great classes of 

 vertebrates Mammals, Birds, Reptiles, Amphibians, 

 and Fishes descend from one prototype, seeing 

 that all animals comprised in these classes possess, 

 especially during the embryonic state, a large 

 number of common characteristics. All vertebrates 

 must descend from some pisciform stock, which has 

 passed through stages similar to that of the Lepi- 

 dosiren, of the Ganoid Fishes, and lower still of the 

 Amphioxus. From this last, the lowest in the scale 

 of all existing vertebrates, and entirely deprived 

 of a cerebral bulb, he passes, following the researches 

 of Goodsir, to the larvae of the Ascidians furnished 

 with the rudiment of a spinal cord that is to say, 

 to the Marine Worms. 



