674 TBE DESCENT OF MAN 



were produced during each successive generation, and were 

 always crossed together; then the slaty females would have, 

 if I may use the expression, much blue blood in their veins, 

 for their fathers, grandfathers, etc., will all have been blue 

 birds. Uader these circumstances it is conceivable (though 

 I know of no distinct facts rendering it probable) that the 

 slaty females might acquire so strong a latent tendency to 

 pale-blueness, that they would not destroy this color in their 

 male ofEspring, their female offspring still inheriting the 

 slaty tint. If so, the desired end of making a breed with 

 the two sexes permanently different in color might be 

 gained. 



The extreme importance, or rather necessity, in the 

 above case of the desired character, namely, pale-blueness, 

 being present though in a latent state in the female, so that 

 the male offspring should not be deteriorated, will be best 

 appreciated as follows: The male- of Scemmerring's pheasant 

 has a tail thirty-seven inches in length, while that of the 

 female is only eight inches; the tail of the male common 

 pheasant is about twenty inches, and that of the female 

 twelve inches long. Now if the female Soemmerring pheas- 

 ant with her short tail were crossed with the male common 

 pheasant, there can be no doubt that the male hybrid off- 

 spring would have a much longer tail than that of the pure 

 offspring of the common pheasant. On the other hand, if 

 the female common pheasant, with a tail much longer than 

 that of the female Soemmerring pheasant, were crossed with 

 the male of the latter, the male hybrid offspring would have 

 a much shorter tail than that of the pure offspring of Scem- 

 merring's pheasant.* 



Our fancier, in order to make his new breed with the 

 males of a pale-blue tint, and the females unchanged, 

 would have to continue selecting the males during many 



• Temminck says that the tail of the female Fhasianns Soemmerringii is 

 only six inches long. "Planches colorizes," vol. v., 1838, pp. 481 and 488: 

 the measurements above given were made for me by Mr. Sclater. For the 

 ecnunon pheasant, see Uacgillivray, "Hist. Brit. Birds," roL i. pp. 118-121. 



