64 DISCONTINUOUS VAEIATION. 



one had 101 florets, the commonest form having 47 

 florets. 



Let us now return to the cases of dimorphism men- 

 tioned at the beginning of the chapter. Instances were 

 there adduced in which the dimorphism was slight, 

 fairly marked, or so great that the two forms scarcely 

 overlapped at all. To what may such dimorphism be 

 due? Bateson points out that a dimorphic condition 

 may have arisen from a previous monomorphic one, or 

 it may always have been present since the character was 

 first acquired. As already stated, the first view is the 

 one which finds favour in the eyes of most biologists, 

 but on the other hand there is a certain amount of evi- 

 dence to show that the second view may hold good, at 

 least in some cases. It is a well-known fact that when 

 two breeds are crossed, their characters do not always 

 blend, but are transmitted in an unmodified state to the 

 offspring from one or from both parents. For instance, 

 in breeding game fowls, if one crosses a black with a 

 white game, birds of both breeds of the clearest colour 

 are obtained. " Sir R. Heron crossed during many 

 years white, black, brown, and fawn-coloured Angora 

 rabbits, and never once got these colours mingled in the 

 same animal, but often got all four colours in the same 

 litter." * Again, Miss E. A. Saunders f has recently 

 made observations on Biscutella lavigata, a cruciferous 

 plant occurring as a perennial herb in the alpine and 

 sub-alpine regions of middle and southern Europe. It 

 was observed by Bateson that this species exhibits two 

 distinct forms, which exist side by side, the one hairy 



* " Animals and Plants," vol. ii. p. 70. 

 fProc. Roy. Soc., vol. Ixii. p. 11. 



