92 



OX CERTAIN CHARACTERS 



Chap. XV. 



which do not now intercross, either would do so under differ 

 conditions, or that they formerly fertilised each other at int™ 



the means for 

 and they will do 



they become ext 



effecting this being generally still 

 so again at some future period, unless indeed 



On this view alone, many points 



structure and action of the reproductive organs in hermaphrodite 

 plants and animals are intelligible,— for instance, the male and 

 female organs never being so completely enclosed as to render 

 access from without impossible. Hence we may conclude that 

 the most important of all the means for giving uniformity 

 to the individuals 



of occasionally int< 



of 



same sr 



present, with all organic bein 



namely, the capac 

 present, or has been formerly 



On certain Characters not blending. —When two breeds are crossed their 

 characters usually become intimately fused together ; but some characters 

 refuse to blend, and are transmitted in an unmodified state either from 

 both parents or from one. When grey and white mice are paired, the 

 young are not piebald nor of an intermediate tint, but are pure white or 

 of the ordinary grey colour : so it is when white and common collared turtle- 

 doves are paired. In breeding Game fowls, a great authority, Mr. J. 

 Douglas, remarks, " I may here state a strange fact : if you cross' a black 

 with a white game, you get birds of both breeds of the clearest colour." 

 Sir E. Heron crossed during many years white, black, brov>m, and fawn- 

 coloured Angora rabbits, and never once got these colours mingled in 

 the same animal, but often all four colours in the same litter. 17 Additional 

 cases could be given, but this form of inheritance is very far from universal 

 even with respect to the most distinct colours. When turnspit dogs and ancon 

 sheep, both of which have dwarfed limbs, are crossed with common breeds, 

 the offspring are not intermediate in structure, but take after either parent. 

 When tailless or hornless animals are crossed with perfect animals, it 

 frequently, but by no means invariably, happens that the offspring are 





x " Extract of a letter from Sir E. 

 Heron, 1838, given me by Mr. Yarrell. 

 With respect to mice, see « Annal. des 

 Sc. Nat,' torn. i. p. 180; and I have 

 heard of other similar cases. For 

 turtle-doves, Boitard and Corbie, 'Les 

 Pigeons/ &c, p. 238. For the Game fowl, 



see Eenggcr, 



South American dora, 

 1 Siiugethiere von Paraguay,' s. 152 : 

 but I saw in the Zoological Gardens 

 mongrels, from a similar cross, which 

 were hairless, quite hairy, or hairy 

 in patches, that is, piebald with hair. 

 For crosses of Dorking and other fowls, 



'The Poultry Book/ 1866, p. 128. For see ' Poultry Chronicle/ vol. ii. p. 355. 



crosses of tailless fowls, see Bechstein, About the crossed pigs, extract of letter 



'Naturges. Deutsch/ b. iii. s. 403. from Sir E. Heron to Mr. Yarrell. 



Bronn, < Geschichte der Natur/ b. ii. s. For other cases, see P. Lucas, 'Hered. 



170, gives analogous facts with horses. Nat./ torn. i. p. 212. 



On the hairless condition of crossed 





