HETEROCHROSIS IN ESSEX BIRDS AND THEIR EGGS. 199
are not applicable at present, but although we have no knowledge
that it has been used we do not see any reason why albinism
should not be used for eggs which are abnormally white or show
a tendency in this direction. We have, therefore, used these
terms as far as possible and listed the remainder of the cases as
unplaced.
ALBINISM.
British Jay. Garrulus glandarius rufitergum Hart.
C/4, Epping Forest, 15 May, 1904. This set contains one
pure white egg. F. C. Hiden. Ref: A. History of the
Birds of Essex.
Linnet. Carduelis c. cannabina (L.). A plain white variety of
egg is not uncommon in the Felsted district. Ref: Felsted
School Scientific Soc. Report No. 25.
Skylark. Alauda a. arvensis L.
C/3, white eggs, Canvey Island, 24 April, 1882. Ref.: The
Birds of Essex (Christy).
British Robin. Erithacus rubecula mniophilus Hart.
Two nests with white eggs, Chelmsford, 1876.
Nest, 2 pure white and 2 very slightly spotted eggs, Chelms-
ford, June, 1877.
Another nest, 2 white eggs, Chelmsford, July, 1877.
C/4, white eggs, Danbury, May, 1888.
Mr. J. H. Owen has adduced evidence of heredity in abnormal
egg-colouration in this species. In 1925 he found a nest
with 5 pure white eggs near Great Waltham. In 1926 he
found three nests in one week in the same neighbourhood
all with the same type of egg and a fourth nest was
found with very poorly marked eggs. He found six nests
in all of the above Robin but he could not say that any
broods were raised as all the nests were destroyed. Ref.:
The Birds of Essex (Christy); The Zool., 1888, p. 390;
British Birds (Mag.), vol. 20, p. 273.
ERYTHRISM.
Hawfinch. Coccothraustes c. coccothraustes (L.).
C/4, Essex, May, 1889, ground colour distinctly reddish-
brown, with large blotches, scrolls and line-markings of
deep reddish-brown and underlying purplish shell-mark-
ings. Ref.: Bulletin, Brit. Ornith Club, vol. 23, p. 59.