142 THE HISTORY 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, ete. 
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 tothe most important internal parts ; there even occur 
great modifications of the skeleton and of the muscular 
