134 THE DOCTRINE OF DESCENT, 



phagus is of great size, barely separated from tlie crop, 

 and is capable of inflation. A second group include.^ 

 Carriers, Runts, and Barbs, which possess in common 

 a long beak, with the skin over the nostrils swollen 

 and often carunculated or wattled, and the skin round 

 the eyes bare and likewise carunculated. To another 

 group, with shorter beak, and the skin round the eyes 

 only slightly developed, belongs the Fantail, in which 

 the normal number of twelve tail feathers may rise to 

 forty-two with aborted oil-gland ; also the Tumbler, in 

 v/hich the beak becomes extremely short, and a sickly 

 disposition of the brain, produced and exaggerated by 

 selection, and manifesting itself by tumbling, has been 

 transmitted for more than 250 years, and has become 

 established as the characteristic of a race. In the fourth 

 group, the Trumpeter occupies a prominent position, on 

 account of its peculiar voice ; likewise the Laugher, or 

 Indian turtle-dove, comprising several sub-races scarcely 

 differing in structure from the rock-pigeon (Columba 

 livia). The latter is divided into several geographically 

 distinct races, ranging from the coasts of the Faroe 

 Islands and Scotland to the shores of the Mediter- 

 ranean and to India ; and the most minute investi- 

 gation, whether the incredibly divergent races of 

 domestic pigeons are derived from eight or nine wild 

 species or solely from the wide-spread rock pigeon, 

 results decidedly in favour of the latter alternative. 

 Proportional dimensions, colouring, and parts of the 

 skeletons which differ from one another far more widely 

 in the various races than they do in well marked species 

 of the same genus, or even family, are modified under 

 the hand and according to the will of man ; and, more- 



