22 DOMESTIC PIGEONS. Chap. I. 



touch; the oil-gland is quite aborted. Several other 

 less distinct breeds might have been specified. 



In the skeletons of the several breeds, the develop- 

 ment 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 number of 

 the caudal and sacral vertebrae vary ; as does the number 

 of the ribs, together with their relative breadth and the 

 presence of processes. The size and shape 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 mouth, 

 the proportional length of the eyelids, of the orifice of 

 the nostrils, of the tongue (not always in strict correla- 

 tion witli the length of beak), the size of the crop and 

 of the upper part of the oesophagus ; the development 

 and abortion of the oil-gland ; the number of the primary 

 wing and caudal feathers ; the relative length of wing 

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

 length of leg and of the feet ; the number of scutellae 

 on the toes, the development of skin between 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 differs remarkably ; as does 

 in some breeds the voice and disposition. Lastly, in 

 certain breeds, the males and females have come to 

 differ to 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, I think, 

 be ranked by him as well-defined species. Moreover, 

 I do not believe that any ornithologist would place 



