Chap. V. 



OSTEOLOGICAL DIFFERENCES. 



163 



of selection, we ought not to expect to find great and constant 

 differences in the skeleton ; for fanciers can neither see, nor do 

 they care for, modifications of structure in the internal frame- 

 work. Nor ought we to expect changes in the skeletons from 

 changed habits of life; as every facility is given to the most 

 distinct breeds to follow the same habits, and the much modified 

 races are never allowed to wander abroad and procure their own 

 food in various ways. 

 Moreover, I find, on 

 comparing the ske- 

 letons of Columba 

 livia, oenas, palum- 

 hus, and turtur, 

 which are ranked 

 by all systematists 

 in two or three dis- 

 tinct though allied 

 genera, that the 

 differences are ex- 

 tremely slight, cer- 

 tainly less than be- 

 tween the skeletons 

 of some of the most c 

 distinct domestic 

 breeds. How far 

 the skeleton of the 

 wild rock-pigeon is 

 constant I have no 

 means of judging, 

 as I have examined 

 only two. 



Skull — The indivi- r> 

 dual bones, especially 

 those at the base, do 

 not differ in shape. 

 But the whole skull, 

 in its proportions, out- 

 line, and relative direc- 

 tion of the bones, differs greatly in some of the breeds, as may be seen 

 by comparing the figures of (a) the wild rock-pigeon, (b) the short- 

 Si 2 



a TvnV i ° f Pi S eons viewed laterally, of natural size. 

 A. Wild Rock-pigeon, Columba livia. B. Short- faced 

 tumbler. C. English Carrier. D. Bagadotten Carrier. 



