Alfred Russel Wallace

“ The families and genera of insects are so immensely numerous, probably exceeding fifty-fold those of all other land animals, that for this cause alone it would be impossible to enter fully into their distribution. It is also quite unnecessary, because many of the groups are so liable to be transported by accidental causes, that they afford no useful information for our subject; while others are so obscure and uninteresting that they have been very partially collected and studied, and are for this reason equally ineligible. ”

“ I have therefore selected a few of the largest and most conspicuous families, which have been so assiduously collected in every part of the globe, and so carefully studied at home, as to afford valuable materials for comparison with the vertebrate groups, when we have made due allowance for the dependence of many insects on peculiar forms of vegetation, and the facility with which many of them are transported either in the egg, larva, or perfect state, by winds, currents, and other less known means. ”

“ The classes of the vertebrata, according to both the authors above quoted, are: 1. Mammalia. 2. Aves. 3. Reptilia. 4. Amphibia. 5. Pisces, in which order they will be taken here.
The sub-classes and orders of mammalia are as follows:
MAMMALIA.
The above series of orders is arranged according to Professor Flower's Osteology of Mammalia, and they will follow in this succession throughout my work. ”

“ The parrots and the pigeons form each a separate order. The old groups of Grallæ and Anseres are preserved, as more convenient than breaking them up into widely separated parts; for though the latter plan may in some cases more strictly represent their affinities, its details are not yet established, nor is it much used by ornithologists. In accordance with these views the following is the series of orders and families of birds adopted in this work:
Class—AVES.
The Passeres consist of fifty families, which may be arranged and grouped in series as follows. ”

“ Of course this reasoning will only apply, in cases where there are no unusual means of dispersal, nor any exceptional causes which might determine a scattered distribution.
From the considerations now adduced it becomes evident, that it is of the first importance for the success of our inquiry to secure a natural classification of animals, especially as regards the families and genera. The higher groups, such as classes and orders, are of less importance for our purpose ”

“ The flamingoes are usually placed in this order, but their habits best assort with those of the waders.
The last order of birds is the Struthiones or Ratitæ, considered by many naturalists to form a distinct sub-class. It consists of comparatively few species, either living or recently extinct.
REPTILES.
In reptiles I follow the classification of Dr. Günther as given in the Philosophical Transactions, vol. clvii., p. 625. He divides the class into five orders as follows:—
In the arrangement of the families comprised in each of these orders I also follow the arrangement of Dr. ”

“ G. R. Waterhouse more than thirty years ago, and succeeding authors have done little more than follow his arrangement with unimportant modifications. Professor Lilljeborg, of Upsala, has however made a special study of this group of animals, and has given an original and detailed classification of all the genera. (Systematisk Öfversigt af de Gnagande Däggdjuren, Glires. Upsala, 1866.) I follow this arrangement with a few slight modifications suggested by other naturalists, and which make it better adapted for the purposes of this work.
Order—RODENTIA.
The Edentata have been classified by Mr. ”