42 THE SCIENCE OF LIFE. 



opinions to careful consideration. He says : " It is my 

 opinion that naturalists are chasing a phantom, in their 

 search after some material gradation among created be- 

 ings, by which the whole Animal Kingdom may have 

 been derived by successive development from a single 



germ, or from a few germs It is contradicted by the 



facts of Embryology and Palaeontology, the former show- 

 ing us norms of development as distinct and persistent 

 for each group as are the fossil types of each period re- 

 vealed to us by the latter." " If they are linked together 

 as a connected series, then the lowest Acaleph should 

 stand next in structu/e above the highest Polyp ; and 

 the lowest Echinoderm next above the highest Acaleph. 

 So far from this being the case, there are, on the con- 

 trary, many Acalephs which, in their specialization, are 

 unquestionably lower in the scale of life than some 

 Polyps, while there are some Echinoderms lower in the 

 same sense than many Acalephs." He shows that the 

 same principle applies to classes in other types: "There 

 are some members of the higher classes that are inferior 

 in organization to some members of the lower classes." 

 The same thing is true in Embryology : " A Vertebrate 

 never resembles at any stage of its growth any thing but 

 a Vertebrate, or an Articulate any thing but an Articu- 

 late, or a Mollusk any thing but a Mollusk, or a Radiate 

 any thing but a Radiate." Geologically, also, we see no 

 transition between types. " In the earliest fossiliferous 

 strata there were the three classes of Radiates, two of 

 the classes of Articulates, and one of the classes of Ver- 

 tebrates." The Geographical Distribution of animals 

 proves the same thing. Thus Agassiz proves that the 



