Principles of Classification as Illustrated by Studies of Arachnida

Abstract

In a technical discussion of the classification of Arachnida in general and the Araneae (spiders) in particular the basic principle that "taxonomy is the mirror of evolution is emphasized. In accord with this principle criticisms are made of those systems of classification which fail to give full value to internal characters. Particularly in spiders classifications based almost entirely on the external genitalia of one sex are bound to be faulty because there are undoubtedly present internal characters which should have precedence over the genital ones, even though these characters may not now be known to arachnologists. The author justifies his own classifications which were made to conform with what he believes to be basic evolutionary trends.