104 Review of Darwin 



tumbling in the air head over heels. The runt is a bird of great 

 size, 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 car- 

 rier, 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 in in- 

 flating, may well excite astonishment and even laughter. The 

 turbit has a very short and conical beak, with a line of reversed 

 feather down the breast ; and it has the habit of continually ex- 

 panding 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 tailfeathers. The trumpeter and laugher, as 

 their names express, utter a very different coo from the other 

 breeds. The fantail has thirty or even forty tailfeathers, 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 have been specified." 



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

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

 ormously. 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 eye- 

 lids, 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 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 



