SEXUAL SELECTION. 269 



intemperance during manhood, and is transmitted from the 

 father to his sons in a much more marked manner than to 

 his daughters. 



In the various domestic breeds of sheep, goats, and 

 cattle the males differ from their respective females in 

 the shape or development of their horns, forehead, mane, 

 dewlap, tail and hump on the shoulders; and these pecu- 

 liarities, in accordance with our rule, are not fully devel- 

 oped until a rather late period of life. The sexes of dogs 

 do not differ, except that in certain breeds, especially in 

 the Scotch deer-hound, the male is much larger and heavier 

 than the female; and, as we shall see in a future chapter, 

 the male goes on increasing in size to an unusually late 

 period of life, which, according to rule, will account for 

 his increased size being transmitted to his male offspring 

 alone c On the other hand, the tortoise-shell color, which 

 is confined to female cats, is quite distinct at birth, and 

 this case violates the rule. There is a breed of pigeons in 

 which the males alone are streaked with black, and the 

 streaks can be detected even in the nestlings; but they 

 become more conspicuous at each successive moult, so that 

 this case partly opposes and partly supports the rule. With 

 the English carrier and Pouter pigeons, the full develop- 

 ment of the wattle and crop occurs rather late in life, 

 and conformably with the rule, these characters are trans- 

 mitted in full perfection to the males alone. The follow- 

 ing cases perhaps come within the class previously alluded 

 to, in which both sexes have varied in the same manner at 

 a rather late period of life, and have consequently trans- 

 ferred their new characters to both sexes at a corresponding 

 late period, and if so, these cases are not opposed to our 

 rule; there exist sub-breeds of the pigeon, described by 

 Neumeiste?,* in which both sexes change their color during 

 two or three moults (as is likewise the case with the Almond 

 Tumbler); nevertheless, these changes, though occurring 

 rather late in life, are common to both sexes. One variety 

 of the canary-bird, namely, the London Prize, offers a 

 nearly analogous case. 



With the breeds of the fowl the inheritance of various 

 characters by one or both sexes seems generally determined 



* " Das Ganze der Taubenzucbt," 1837, ss. 21, 24. For tbe case of 

 the streaked pigeons, see Dr. Chapuis, " Le pigeon voyageur Beige," 

 1S65, p. 87, 



