218 ESSAY ON CLASSIFICATION. 



kingdom, I shall not use it in future, but prefer the 

 term branch of the animal kingdom, because the term 

 type is employed in too many different acceptations, and 

 quite as commonly to designate any group of any kind, 

 or any peculiar modification of structure stamped with a 

 distinct and marked character, as to designate the primary 

 divisions of the animal kingdom. We speak, for instance, 

 of specific types, generic types, family types, ordinal types, 

 classic types, and also of a typical structure. The use of the 

 word type in this sense is so frequent on almost everypage of 

 our systematic works, in Zoology and in treatises of compara- 

 tive anatomy, that it seems to me desirable, in order to avoid 

 every possible equivocation in the designation of the most 

 important great primary divisions among animals, to call 

 them branches of the animal kingdom, rather than types. 

 That, however, our systems are more true to nature 

 than they are often supposed to be, seems to me to be 

 proved by the gradual approximation of scientific men to 

 each other, in their results, and in the forms by which 

 they express those results. The idea which lies at the 

 foundation of the great primary divisions of the animal 

 kingdom is, the most general conception possible in con- 

 nection with the plan of a definite creation ; these divi- 

 sions are, therefore, the most comprehensive of all, and 

 properly take the lead in a natural classification, as repre- 

 senting the first and broadest relations of the different 

 natural groups of the animal kingdom, the general for- 

 mula winch they each obey. What we call a branch 

 expresses, in fact, a purely ideal connection between 

 animals, the intellectual conception which unites them in 

 the creative thought. It seems to me, that the more we 

 examine the true significance of this kind of groups, the 

 more we shall be convinced that they are not founded 



