Chap. L] DOMESTIC PIGEONS. 25 



tlieir 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 expanded, and are carried so 

 erect, that in good birds the head and tail touch : the 

 oil-gland is quite aborted. Several other less distinct 

 breeds might be 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 caudal and sacral 

 vertebrae vary in number ; as does the number of the 

 ribs, together with their relative breadth and the pre- 

 sence 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 

 correlation with the length of beak), the size of the crop 

 and of the upper part of the oesophagus ; the develop- 

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

 primary wing and caudal feathers ; 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 

 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, and in 



