20 ON THE ORIGIN OF SPECIES 



gape of mouth. The short-faced tumbler has a beak J 

 in outline almost like that of a finch ; and the common 

 tumbler has the singular inherited habit of flying at a 

 great height in a compact flock, and tumbling in the 

 air head over heels. The runt is a bird of great size, j 

 with long, massive beak and large feet ; some of the 

 sub-breeds of runts have very long necks, others very 

 long wings and tails, others singularly short tails. 

 The barb is allied to the carrier, but, instead of a very 

 long beak, has a very short and very broad one. The 

 pouter has a much elongated body, wings, and legs ; \ 

 and its enormously developed crop, which it glories I 

 in inflating, may well excite astonishment and even \ 

 laughter. The turbit has a very short and conical beak, \ 

 with a line of reversed feathers down the breast ; and J 

 it has the habit of continually expanding slightly the ; 

 upper part of the oesophagus. The Jacobin has the 

 feathers so much reversed along the back of the neck 

 that they form a hood, and it has, proportionally to its 

 size, much elongated wing and tail feathers. The 

 trumpeter and laugher, as their names express, utter a J 

 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 members of the 

 great pigeon family ; and 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 1 

 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 J 

 the degree of divergence and relative size of the two I 

 arms of the furcula. The proportional width of the J 

 gape of mouth, the proportional length of the eyelids, ] 



