PRINCIPLES AND PRACTICE OF CLASSIFICATION. 



65 



later of these to die, portions of skin, feathers, etc., having been found. With Moa-remains 



are found those of Harpagornis, a raptorial bird large enough to have preyed upon Moas. 



Finally, various birds have been exterminated in historic times, 



some of them within the lifetime of persons now living. The Dodo 



of Mauritius, Didus ineptus, is the most celebrated one of these, of 



the living of which we have documentary evidence down to 1681 ; 



the Solitaire of Rodriguez, Pezopliaps solitarius, the Geant, Legua- 



tia gigantea, and several others of the same Mascarene group of 



islands, are in similar case. The Great Auk, Plautus impennis, is 



supposed to have become extinct in 1844 ; a Parrot, Nestor pro- 



ductus, was last known to be living in 1851 ; various Parrots, Rails, 



and other birds have likewise disappeared within a very few years. 



At least two North American birds, Pallas' Cormorant, Phalacrocorce 



perspicillatus, and the Labrador Duck, Camjjtolcernus labradorius, 



are lately deceased. (See Newton, Ency. Brit., 9th ed., art. Birds.) 



§2. 



PRINCIPLES AND PRACTICE OF CLASSIFICATION. 



Having seen what a Bird is, and how it is distinguished 

 from other animals, our next business is to inquire how birds are 

 related to and distinguished from one another, as the basis of 



Classification : a prime object of ornithology, without the at- 

 tainment of which birds, however pleasing they are to the senses, do 

 not satisfy the mind, which always strives to make orderly disposi- 

 tion of its knowledge, and so discover the reciprocal relations and 

 interdependencies of the things it knows. Classification presup- 

 poses that there do exist such relations, according to which we may 

 arrange objects in a manner which facilitates their comprehension, by bringing together what 

 is like, and separating what is unlike ; and that such relations are the results of evolutionary 

 law. It is, therefore. 



Fig. 17. — Restoration of 

 Leguatia gigantea. From 

 Packard, after Schlegel. 



Taxonomy (Gr. Ta|is, taxis, arrangement, and vofios, nomos, law), or the rational, 

 lawful disposition of observed facts. Just as taxidermy is the art of fixing a bird's skin in a 

 natural manner, so taxonomy is the science of arranging birds in the most natural manner — 

 in the way that brings out most clearly their natural affinities, and so shows them in their 

 proper relations to each other. This is the greatest possible help to the memory in its 

 attempt to retain its hold upon great numbers of facts. But taxonomy, which involves 

 consideration of the greatest problems of ornithology, as of every other branch of biology 

 (biology being the science of life and living things in general), is beset with gravest diffi- 

 ■culties, springing fnnn our defective knowledge. We could only perfect our taxonomy by 

 having before us a specimen of every kind of bird that exists, or ever existed ; and by 

 thoroughly understanding how each is related to and differs from every other one. This is 

 obviously impossible; in point of fact, we do not know all the birds now living, and only 

 a small number of extinct birds have come to light; so that many of the most important 

 links in tlie chain of evidence are missing, and many more cannot be satisfactorily joined 

 together. With these springs of ignorance and sources of error must be reckoned also the 

 risk of going wrong through natural fallibility of the human mind. The result is, that 

 "natural classification,'' like the elixir of life or the philosopher's stone, is a goal still dis- 

 tant ; and as a matter of fact, the present state of the ornithological system is far from 



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