92 GENERAL ORNITHOLOGY part ii 



graphical distribution and geological succession ; of their probable 

 ancestr}^ ; of their every relation to one another and to all other 

 animals, including man, — in short, of their significance in Nature. 

 The first business of Ornithology is to define its ground — to answer 

 the question 



What is a Bird ? — There is every reason to believe that a Bird 

 is a greatly modified Eeptile, being the oflfspring by direct descent 

 of some reptilian progenitor ; and there is no reason to suppose 

 that any bird ever had any other origin than by due process of 

 hatching out of an egg laid by its mother after fecundation by its 

 father, — just what we believe to have been the invariable method 

 during the period of the world known to human history. There is 

 no reason to believe that any bird was ever originally created and 

 endowed with the characters it now possesses ; but that every bird 

 now living is the naturally modified lineal descendant of parents 

 that were less and less like itself, and more and more like certain 

 reptiles, the further removed they were in the line of avian 

 ancestry from such birds as are now living. This is the Darwinian 

 logic of observed facts, upon which the modern Theory of Evolution 

 is based, in opposition to the tradition of the special creation of 

 every species of animal ; which latter has no scientific basis 

 whatever, and is consequently accepted as true by few thoughtful 

 persons who are capable of forming independent judgments. 

 Accordingly, 



Bipds and Reptiles — even those of the present geologic epoch 

 — share so many and so important structural characters, that the 

 chiefs of science of our day are wont to unite the two classes, Aves 

 and Keptilia, in one primary group of the Vertebrata, or animals 

 with a backbone. This group is called Saumpsida, or reptiliforms ; 

 it is contrasted, on the one hand, with Ichfhyopsida, or fish -like 

 vertebrates, including Batrachians as well as Fishes ; and, on the 

 other, with Mammalia, the province of the Vertebrata which in- 

 cludes Man and all other animals that suckle their young. We 

 find that 



The Saupopsida (Gr. o-avpos, sauros, a reptile ; oipis, opsis, appear- 

 ance), or lizard-like Vertebrates, agree with one another, and differ 

 from other animals, in the following important combination of char- 

 acters, substantially as laid down by Professor Huxley, — some of 

 the characters being shared by the Ichthyopsida, and some by the 

 Mammalia, but the sum of the characters being distinctive of Saurop- 

 sida: they are all oviparous (laying eggs hatched outside the body 

 of the parent), or ovoviviparous (laying eggs hatched inside the body 

 of the parent), being never viviparous (bringing forth alive young 

 nourished before birth by the blood of the mother). The embryo 

 develops those fcetal organs called amnion and allantois, and is 



