ON EXPERIMENTAL STUDIES IN THE PHYSIOLOGY OF HEREDITY. 347 
rp.s is distinguishable from 7. p. Extracted r and p of course are pure 
from rp, and from p and 7 respectively. 
The scheme of descent is as follows :— 
TXS pxs 
TS ox ps 
ee 
TS Tp x TP i SS 
Lez _ lpp irp7p Iss 
27s 2ps 277.8 
27pr 
27p.p 
2rp 
Seca 
Te « Tp TPXs 
om 
Ips 
1 1 1 ile 
ee uctaze ee a a 
27727 
27pPp 
2rp 
In view of these facts we are determining the condition of thorough- 
bred Malays in respect of comb. Of the five types which theory shows 
to be possible, four have been found in pure Malays or Malay Bantams 
(proved by crosses with s), Malay breeders often get p birds from pure- 
bred rp, and such p birds are not able to transmit 7 or rp. It is, however, 
doubtful whether r and s birds occur in pure breeding, a fact which 
raises a distinct problem not yet solved. We suspect the existence of a 
complexity dependent on sexual differentiation. 
Il. Sweer Peas.—Shapes.—‘ Cupids’ and ‘Snapdragons’ Mendelize 
simply. Long and round pollens do the same, but in certain families 
there is some problematical coupling with colour. 
Colour.—Numerous lines of experiment are being followed. The 
following case illustrates the nature of the work : E. Henderson (white) . 
