The Evidence from Sexual Characters. 219 



alike ; thus the female trumpeter lias a tuft like that of 

 the male, and the hood of the Jacobin and the frill of 

 the turbit are alike in both sexes ; but wherever the 

 sexes do differ the males are, as a rule, more modified 

 than the females. 



In all ordinary domesticated breeds as well as in most 

 wild species, the number of tail-feathers is twelve, but 

 in the fan-tail breed there are from thirty to forty, and 

 they are permanently expanded like a fan. We must 

 believe that this deviation from the typical number of 

 tail-feathers in the pigeon family is due to recent modi- 

 fication, and we find that the number is often much 

 greater in the male fan-tail than it is in the female. 



The pouter pigeon is a very remarkable domestic 

 breed. All domestic pigeons have some slight power of 

 inflating the crop, but this power is so greatly developed 

 in the pouter breed that the bird is able to blow himself 

 up like a balloon, and Darwin says that after one of his 

 pouters had swallowed a good meal of peas, he could 

 hear the peas rattle as if in a bladder as the bird flew 

 through the air with its crop inflated. Darwin says 

 that the males pout more than the females, and glory in 

 this power, and strut about puffed up with wind and 

 pride. He also says that it is a very unusual thing for 

 the female to excel -in pouting. We must therefore be- 

 lieve that the male pouter has departed further than 

 the female from ordinary pigeons. 



The tumbling habit of tumbler pigeons is perhaps the 

 most remarkable of all the hereditary modifications of 

 domestic animals which man has produced. The fol- 

 lowing account of the English tumbler is quoted by 

 Darwin from Brent: " Every few seconds over they go, 

 one, two, or three somersaults at a time. Here and 

 there a bird gives a very quick and rapid spin, re- 



