Manchester Memoirs, Vol. xlviii. (1904), No. 24. 13 



Bateson :02, note on p. 55 and pp. 24 and 25). 

 This hybrid (I have bred some 350) is never an 

 albino, and it never waltzes : albinism and waltzing there- 

 fore are recessive characters ; and pigmentation and 

 normal progression are the corresponding dominant 

 characters. So that we are crossing a creature — the 

 albino — possessing normality of progression (D) and 

 albinism (R), with another beast which exhibits waltzing 

 movements {R) and the presence of pigment {D). Let us 

 consider the offspring of hybrids thus produced from the 

 point of view of the two pairs of allelomorphs. First, 

 with regard to colour, we should expect 25% albinos which 

 should breed true : this is in fact what we get. Secondly, 

 with regard to their progression, we should expect to find 

 25% waltzing mice : this is very roughly what happens ; I 

 have been unable to determine if they breed true (on the 

 Mendelian hypothesis they should, of course). Now let 

 us look at the offspring of hybrids from dot/i points of 

 view at the same time : one mouse in every four is an 

 albino ; one in every four is a waltzer, so we should expect 

 one in every sixteen to be an albino waltzer. Now these 

 albino waltzers are new things ; and, what is more, they 

 should breed true, because both their characters i^A and 

 W) are recessive. What has happened is that we have 

 taken the recessive character — albinism — from one parent 

 of the hybrid, and the recessive character — 'waltzing' — from 

 the other ; and through the mediation of the hybrid united 

 them in one individual — the new albino waltzer — which 

 will produce nothing but offspring like itself, because its 

 gametes are pure.* I have bred several examples of this 

 new species, but have so far been unable to obtain young 

 from them. 



* I am not sure that this case is not, strictly speaking, an example of a 

 synthetical variation ; at any rate it is a very simple instance of the argu- 

 ment set forth in Bateson :02a p. 29. 



