Chap. XV.] SEXUALLY-LIMITED INHERITANCE. I49 



more probably the speedy and complete loss of the pale- 

 blue color, for the primordial slaty tint would be trans- 

 mitted with prepotent force. Supposing, however, that 

 some pale-blue males and slaty females 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. 

 Under these circiimstances 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 theii' 

 male oiFspring, 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, of the de- 

 sired character in the above case, 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 Soemmerring's pheasant 

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

 female is only eight inclies ; 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 com- 

 mon pheasant, there can be no doubt that the male hybrid 

 offspring 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 her tail nearly 

 twice as long as 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 Scemmerring's pheasant.' 



3 Temminck says that the tail of the female Phasianus Sammerringii 



