Chat. XIV.] CLASSIFICATION. 207 



same organ^ as we have every reason to suppose, has 

 nearly the same physiological value, its classificatory 

 value is widely difEerent. No naturalist can have 

 worked long at any group without being struck with 

 this fact; and it has been fully acknowledged in the 

 writings of almost every author. It will suffice to quote 

 the highest authority, Eobert Brown, who, in speaking 

 of certain organs in the Proteacese, says their generic 

 importance, "like that of all their parts, not only in 

 this, but, as I apprehend, in every natural family, 

 is very unequal, and in some cases seems to be entirely 

 lost." Again, in another work he says, the genera 

 of the Connaracese " differ in having one or more ovaria, 

 in the existence or absence of albumen, in the imbricate 

 or valvular aestivation. Any one of these characters 

 singly is frequently of more than generic importance, 

 though here even when all taken together they appear 

 insufficient to separate Cnestis from Connarus." To 

 give an example amongst insects: in one great division 

 of the Hymenoptera, the antennae, as Westwood has re- 

 marked, are most constant in structure; in another 

 division they differ much, and the differences are of 

 quite subordinate value in classification; yet no one will 

 say that the antennae in these two divisions of the 

 same order are of unequal physiological importance. 

 Any number of instances could be given of the varying 

 importance for classification of the same important or- 

 gan within the same group of beings. 



Again, no one will say that rudimentary or atrophied 

 organs are of high physiological or vital importance; 

 yet-, undoubtedly, organs in this condition are often of 

 much value in classification. ISTo one will dispute that 

 the rudimentary teeth in the upper jaws of young rumi- 



