A. R. Galloway 
25 
It is also a fact that no partly bald plainheads occur in the crested variety — 
a proportion of ^ is necessary according to Davenport's system of allelomorphs : 
see his p. 13. 
Double-Cresting and Baldness. With regard to double-cresting, of which I 
have had considerable experience, we have seen that the proportion of crests was 
doubled. None of these 34 crests and 17 crest-bred plainheads showed any sign 
of general baldness. I have been, however, careful to select perfectly shaped crests 
with closely lying backs. I have often heard of, and seen, partially bald-headed 
crests, which were said to be the result of double-cresting. In these there was 
always some skin affection of an eczematous or parasitic nature, wliich would 
sufficiently account for the condition apart from simple baldness*. 
Results of Double-Cresting. In my experience double-cresting may be continued 
for several generations with the best results as far as shape, droop and radiation 
(for the present-day crest is not " flat " as Davenport quotes from Blakston in 
* Bateson {Mendel's Principles of Heredity, 1909) writes (quotina; Evolution Committee Eeports and 
Davenport): "The crest of the Crested Canaries is always bred for Shows by mating cresteds with 
plain-headed birds." (p. 298.) 
This is, by no means, universally the case, as double-cresting is a well-known method of pairing to 
produce winners. 
" This neatly-laid appearance (of the Crest) is only produced when the bird is heterozygous for the 
crest factor." (p. 298.) 
The following were crests of perfect shape, and prize-winners : 
C. cl. ? (C. cl. xC.v.2: 2. 06). 
a t. ? (C. cl. xC.v.2: 2. '06). 
C. m. S and C. m. ? : 3. '02 had crest-bred father, but both father and mother were bred from 
double-crests. 
In 1894, Mr .Tohn Hector, Aberdeen, bred a green crested hen from double-crests, which gained first 
prizes at Dundee and Aberdeen, and was then sold to Mr Fred. Weinberg, Dundee, who gained many 
leading prizes with it, and believed it to be the best crest he had ever owned. 
Mr Jas. Wallace, Aberdeen, gained 3rd prize, Glass 9, Crystal Palace, 1909, with a clear yellow 
crest which he bred from double-crests. 
Mr F. W. Barnett, Fakenham, Norfolk, who is now, and has been for many years, the much envied 
chief of crest breeders, has favoured me with his experience of double-cresting, which will be found 
to agree with my own. 
Mr Barnett has not exhibited any birds for some years (most winners, however, have been bred 
by him), but he tells me he won at the Crystal Palace ten or twelve years ago with a crested bird bred 
from two crests ; he has bred several others in a similar way which could have won in good company, 
had they been shown by him. His practice, when in need of fresh blood, is to mate a Lancashire Coppy 
(Fig. 4) with a Crest (Fig. 3) which ''hit very well"; he also agrees with me in stating that indis- 
criminate double-cresting often throws mop crests, the reverse of bald heads. These mop crests are not 
the bald heads of the fancier as supposed by Bateson (p. 37). 
" The mating of two crested parents is by several authors said to give rise to some bald birds." 
(p. 37.) 
Bateson here, like Darwin, repeats a belief which undoubtedly does obtain in the fancy, but which 
my experience does not corroborate— for I have never seen baldness which could be attributed to double- 
cresting, and I have seen much of it that could be easily explained by simpler means, e.g. lice, to the 
attacks of which the heads and necks of these heavily feathered birds are specially prone, and which are, 
as a rule, unrecognised by fanciers. 
Darwin also states erroneously that there is a feather-footed breed of canary (1875, The Variation 
of Animals and Plants under domestication. Vol. i. p. 311) (cf. p. 17 above and note on p. 13). 
Biometrika vii 4 
