No. 629] 



DAE WIN AND IIYBEIDIZATION 



549 



When luo l)i-ee(l. m.-o crossed, their cliaracters usually become inti- 

 one (Ic. 2:67). 



As cases in point, Darwin cites the crossing of gray and 

 white mice, the offspring being pure white or gray, but 

 not intermediate, and the crossing of white, black and 

 fawn-colored Angora rabbits, in which the colors are sep- 

 arately inherited, and not combined in the same animal. 

 The non-intermediate character of the inheritance in the 

 case of turnspit dogs and ancon sheep is referred to, as 

 is also the inheritance in the case of tail-less, horn-less 

 breeds. Similar results in the case of stocks, toad-flax 

 and sweet ])eas are cited (lb, p. 68). 



Darwin (Ic, 44 45), in discussing what lie called "j)re- 

 ])()tency/' was dealing in very many case^ with that 

 which we now recognize as simple dominance. For ex- 

 ample, in the crossing of ^nap-dragons, Darwin found 

 that when the normal or irregular-flowered type was 

 crossf^d with the abnormal or regular-flowered type, the 



the hWU'V. 1Mi('S(" 127 hyl.rid ])lants sci t'-rcii i li/cd. yielded 

 ill tlir M'c.nd uvnrraticn irn-uhir t(. ivi^ular phiut^ iii the 

 rath) (.(■ SS lo 'Idiis is very close to the exact 1 ratio 

 which would he rcprrsciitcd by the numbers 85:42. Dar- 

 win, howcxcr, -iiiiplx regards it as a 



Darwin was thus (piite unable, with the iiit oniiation 

 then available, to frame a satisfactorx cxplaiiatioii loi- the 

 various phenomena passing under the iiaine (»l '-pre 

 potency. ' ' 



