DARWIN, AND THE ORIGIN OF SPECIES 193 



laugher, as their names express, utter a very different coo from 

 the other breeds. The fantail has thirty or even forty tail feathers 

 instead of twelve or fourteen, the normal number in all the 

 members of the great pigeon family ; these feathers are kept ex- 

 panded, and are carried so erect, that in good birds the head and 

 tail touch : the oil-gland is quite aborted. Several other less dis- 

 tinct breeds might be specified. 



" In the skeletons of the several breeds, the development of 

 the bones of the face in length and breadth and curvature differs 

 enormously. The shape as well as the breadth and length of 

 the ramus of the lower jaw varies in a highly remarkable manner. 

 The caudal and sacral vertebrae vary in number, as does the num- 

 ber of the ribs, together with their relative breadth and the pres- 

 ence of processes. The shape and size of the apertures in the 

 sternum are highly variable; so is the degree of divergence and 

 relative size of the two arms of the furcula. The proportional 

 width of the gape of the mouth, the proportional length of the 

 eyelids, of the orifice of the nostrils, of the tongue (not always 

 in strict correlation to the length of the beak), the size of the 

 crop and of the upper part of the oesophagus; the development 

 and abortion of the oil-glands ; the relative length of the wing 

 and tail to each other and to the body ; the relative length of 

 the leg and foot, the number of scutellas on the toes, are all 

 points of structure which are variable. The period at which the 

 perfect plumage is acquired varies, as does the state of the down 

 with which the nestling birds are clothed when hatched. The 

 shape and size of the eggs vary. The manner of flight, and in 

 some breeds the voice and disposition, differ remarkably. Lastly, 

 in certain breeds the males and females have come to differ in a 

 slight degree from each other. . . . Altogether, at least a score of 

 pigeons might be chosen which, if shown to an ornithologist, and 

 he were told that they were wild birds, would certainly be ranked 

 by him as well-defined species. 



" Moreover, I do not believe that any ornithologist would, in 

 this case, place the English carrier, the short-faced tumbler, the 

 runt, the barb, pouter, and fantail in the same genus; more espe- 

 cially as in each of these breeds several truly inherited sub-breeds 

 or species, as he would call them, could be shown him." 



