CHAP. X. CLASSIFICATION. 97 



CHAPTEK X. 



ON THE PKINCIPLES OF CLASSIFICATION. 



PEEHAPS some one else, more fortunate than myself, 

 may be able, even without Darwin, to find the guiding 

 clue through the confusion of developmental forms, 

 now so totally different in the nearest allies, now so sur- 

 prisingly similar in members of the most distant groups, 

 which we have just cursorily reviewed. Perhaps a 

 sharper eye may be able, with Agassiz, to make out " the 

 plan established from the beginning by the Creator," l 

 who may have written here, as a Portuguese proverb 

 says " straight in crooked lines." 2 I cannot but think 

 that we can scarcely speak of a general plan, or typical 

 mode of development of the Crustacea, differentiated 

 according to the separate Sections, Orders, and Fami- 

 lies, when, for example, among the Macrura, the Kiver 

 Crayfish leaves the egg in its permanent form ; the 



1 " A plan fully matured in the beginning and und'e via tin gly pursued ;" 

 or "In the beginning His plan was formed and from it He has never 

 swerved in any particular " (Agassiz and Gould, ' Principles of Zoology' ). 



2 " Deos escrive direito em linhas tortas." To read this remarkable 

 writing we need the spectacles of Faith, which seldom suit eyes 

 accustomed to the Microscope, 



H 



