142 THE HISTOHY OF CREATION. 



known fan-tailed pigeon, which spreads its tail like the pea- 

 cock, and carries a number of (from thirty to forty) feathers 

 placed in the form of radii, while other pigeons possess 

 much fewer tail feathers — generally twelve. We may here 

 mention that the number of feathers on the tails of birds is 

 considered by naturalists of great value as a systematic dis- 

 tinction, so that whole orders can thereby be distinguished. 

 For example, singing birds, almost without exception, possess 

 twelve tail feathers ; chirping birds (Strisores) ten, etc. 

 Several races of pigeons, moreover, are characterized by a 

 tuft of neck feathers, which form a kind of periwig ; others 

 by grotesque transformation of their beaks and feet, by pecu- 

 liar and often very remarkable decorations, as, for example, 

 skinny lappets, which develop on the head ; by a large 

 crop, which is formed by the gullet being strongly inclined 

 forward, etc. Remarkable, also, are the strange habits which 

 many pigeons have acquired ; for example, the turtle pigeons 

 and the trumpeters with their musical accomplishments, the 

 carriers with their topographical instinct. The tumblers 

 have the strange habit of ascending into the air in great 

 numbers, then turning over and falling down through the 

 air as if dead. The ways and habits of these endless races 

 of pigeons — the form, size, and colour of the individual parts 

 of their bodies, and their proportions, differ in a most 

 astonishing degree from one another ; in a much higher de- 

 gree than is the case with the so-called good species, or even 

 with the perfectly distinct genera, of wild pigeons. And 

 what is of the greatest importance, is the fact that these 

 differences are not confined to the external form, but extend 

 even to the most important internal parts ; there even occur 

 great modifications of the skeleton and of the muscular 



