CLASSIFICATION 461 



Monachanthus, Myanthus, and Catasetum, which had previ- 

 ously been ranked as three distinct genera, were known to be 

 sometimes produced on the same plant, they were immedi- 

 ately considered as varieties ; and now I have been able to 

 show that they are the male, female, and hermaphrodite 

 forms of the same species. The naturalist includes as one 

 species the various larval stages of the same individual, how- 

 ever much they may differ from each other and from the 

 adult, as well as the so-called alternate generations of Steen- 

 strup, which can only in a technical sense be considered as 

 the same individual. He includes monsters and varieties, not 

 from their partial resemblance to the parent-form, but be- 

 cause they are descended from it. 



As descent has universally been used in classing together 

 the individuals of the same species, though the males and 

 females and larvae are sometimes extremely different ; and as 

 it has been used in classing varieties which have undergone 

 a certain, and sometimes a considerable amount of modifica- 

 tion, may not this same element of descent have been uncon- 

 sciously used in grouping species under genera, and genera 

 under higher groups, all under the so-called natural system? 

 I believe it has been unconsciously used; and thus only can 

 I understand the several rules and guides which have been 

 followed by our best systematists. As we have no written 

 pedigrees, we are forced to trace community of descent by 

 resemblances of any kind. Therefore v^^e choose those char- 

 acters which are the least likely to have been modified, in 

 relation to the conditions of life to which each species has 

 been recently exposed. Rudimentary structures on this view 

 are as good as, or even sometimes better than, other parts 

 of the organisation. We care not how trifling a character 

 may be — let it be the mere inflection of the angle of the jaw, 

 the manner in which an insect's wing is folded, whether the 

 skin be covered by hair or feathers— if it prevail through- 

 out many and different species, especially those having very 

 different habits of life, it assumes high value; for we can 

 account for its presence in so many forms with such differ- 

 ent habits, only by inheritance from a common parent. We 

 may err in this respect in regard to single points of structure, 

 but when several characters, let them l)c ever so trifling, 



