60 GENERAL ORNITHOLOGY. 



What is a Bird? — There is evory reason to believe that a Bird is a greatly iimdiiied 

 Reptile, being the ott'spring 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 liird was ever originally created and endowed with tlie 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 nuire and more like ceitain reptiles, the 

 further removed they were in the line of avian ancestry fi-om such birds as are now living. 

 This is the Darwinian logic of tibserved 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 thought- 

 ful persons who are capable of forming independent judgments. Accordingly, 



Birds and Reptiles — even tlnjse of the jjresent geologic epoch — share so many and so 

 important structui-al characters, that the cliiefs of science of our day are wont to unite the two 

 classes. Ares and Reptilia, in one primary group of the Vertehrata, or animals with a back- 

 bone. This group is called Sauropsida, or rcptiliform ; it is contrasted, ou the one hand, with 

 Icli1hijopsida,or fish-like vertebrates, including Batrachians as well as Fishes; and, on the 

 other, with 3[iiiiimaUa, the province <if the Vertehrata which includes Jlan and all other 

 animals that suckle their young. We tind that 



The Sauropsida (Gr. aavpos, sdiirox, a reptile ; o-^ts, ojisis, appearance), or lizard-like 

 A^ertcbrates, agree with one another, and differ from other animals, in the following important 

 combination of characters, substantially as laid down by Professor Huxley, — some of the char- 

 acters being shared by the Ichtliijopsida, and some by the 3Iammalia, but the sum of the 

 characters being distinctive of SfiKi'Ojjgida : They arc all oviparous (laying eggs hatched out- 

 side the body of the parent), la- ovoviviparous (laying eggs hatched inside the body of the 

 parent), being never viviparous (biiuging forth alive young nourished before birth by the 

 blood of the mother). The embryo develops those fietal organs called amnion and alkmtois, 

 and is nourished before hatching by tlic great quantity of yolk in the egg. There are no 

 jnammary glands to furnish the young with milk after birth. The generative, urinary, and 

 digestive organs come together behind in a common receptacle, the cloaca, or se\i'ev, and their 

 products arc discharged by a single orifice. The kidneys of the early embryo, called Wolffian 

 hndies, are soon replaced functionally by jiermanent kidneys, and structurally by the testes of 

 the male and the ovaries of the female. The cavity of the ciMomen, or belly, is not separated 

 from that of the thorax, or chest, by a complete muscular partition, or diapliracfm. The great 

 lateral luanispheres of the brain are not cininect(>d by a transverse conunissurc, or corpus 

 callosioii. Air is always breathed by true lungs, never liy gills. The blood, which may be 

 ('(dd or hot, has red oval nucleated corpuscles; the lieart has either three or four separate 

 clianibers, — the latter in birds, in which tlie circulatimi of the hot blood is completely double, 

 i.e., in tlie lungs and one side of the heart, in the body at large and the other side of the heart. 

 The aortic arches are several ; or if but one, as in birds, it is the right, not the left as in nuini- 

 mals. The centra, or bodies, of the vertebra? are ossified, but have no terminal c^jfjj/iv.scs. 

 Tlie skull hinges upon the back-bfuie by a single median protuberance, or comh/lc, and the 

 part bearing the condyle is completely ossified. The lower jaM- consists of several separate 

 pieces, the articular one of which hinges upon a movable quadrate bone ; and tlieie are 

 other peculiarities in the formation of the skull. The ankle-joint is situated, not, as in 

 mammals, between the tarsal bones and thijse of the leg, but between two rows of tar.sal bones. 

 The skin is usually covered with outgrowths, in the form of scales or tV'athers. — Dift'erent as 



