230 ESSAY ON CLASSIFICATION 



very favorable sign of our times. It would indeed be a great mistake 

 to assume that it is solely owing to the influence of different authors 

 upon one another; it is, on the contrary, to a very great extent the 

 result of our better acquaintance with Nature. When investigators 

 at all conversant with the present state of our science must possess 

 nearly the same amount of knowledge, it is self-evident that their 

 views can no longer differ so widely as they did when each was famil- 

 iar only with a part of the subject. A deeper insight into the animal 

 kingdom must in the end lead to the conviction that it is not the task 

 of zoologists to introduce order among animals, but that their high- 

 est aim should be simply to read the natural affinities which exist 

 among them, so that the more nearly our knowledge embraces the 

 whole field of investigation, the more closely will our opinions coin- 

 cide. 



As to the value of the classes adopted by Owen, I may further re- 

 mark that recent investigations, of which he might have availed him- 

 self, have shown that the Cirripedia and his Epizoa are genuine 

 Crustacea and that the Entozoa can no longer be so widely separated 

 from the Annellata as in his system. With reference to the other 

 classes, I refer the reader to my criticism of older systems and to the 

 first section of this Chapter. 



It is a gTeat satisfaction for me to find that the views I have advo- 

 cated in the preceding sections, respecting the natural relations of 

 the leading groups of the animal kingdom, coincide so closely with 

 the classification of that distinguished zoologist, Milne-Edwards, 

 lately presented by him as the expression of his present views of the 

 natural affinities of animals He is the only original investigator who 

 has recently given his unqualified approbation to the primary divi- 

 sions first proposed by Cuvier, admitting of course the rectifications 

 among the group of secondary rank rendered necessary by the prog- 

 ress of science, to which he has himself so largely contributed. 



As to the classes adopted by Milne-Edwards, I have little to add to 

 what I have already stated before with reference to other classifica- 

 tions. Though no longer overruling the idea of plan, that of com- 

 plication of structure has still too much influence with Milne-Ed- 

 wards, inasmuch as it leads him to consider as classes groups of ani- 

 mals which differ only in degree and are therefore only orders. Such 

 are no doubt his classes of Molluscoids and those of Worms, besides 



