CC1V 
APPENDIX. 
There appears a considerable variation in the size of individuals, in all the 
larger species of gulls. 
17. Larus Argent atus. Silvery Gull. 
Greenl. Birds, no. 20. Temm. 764 . 
In the Memoir on the Birds of Greenland, the species described under this 
name was identified on the authority of Mr. Temminck with the common her- 
ring gull of our coasts ; the absence of the black markings of the primary quill 
feathers, which alone constitutes the distinction between them, being consi- 
dered by that eminent naturalist as a variation of plumage occasioned by 
climate : thus the Larus Argentatus was made to comprise two varieties, one 
peculiar to the Greenland seas, having the quill feathers a very faint 
ash-colour, with the ends and under parts white, without the admixture of 
black ; and the other the common herring gull. The present Expedition 
has furnished an instance which may be considered to confirm Mr. Tem- 
minck’s decision ; amongst a number of the Greenland variety which had 
their nests on a cliff on one of the North Georgian Islands, one individual 
was observed to have black markings on the wings, and was fortunately se- 
cured : on comparing this specimen with birds which have been killed on 
our own coasts, the black markings of the quill feathers are found to corre- 
spond precisely in shape and situation ; the only perceptible difference being 
that the dark colour is not quite so deep in shade in the Polar as in the 
European specimens. 
18. Larus Eburneus. Ivory Gull. 
Greenl. Birds, no. 21. Temm. 7 69 . 
A fine specimen of a bird of the first year was killed in Davis’ Strait on the 
14th of September, having all the immature markings of the individual 
described by Temminck as shot in Switzerland in March, with the ad- 
dition of numerous spots on the shoulders and spurious wings : this species 
