- ; V ; 
170 Dr Edmonston on the Natural History of some 
The following are the peculiarities on the external appear- 
ance of what may be denominated the black Arctic gull. 
Male . — The crown and sides of the head are black. The 
back, scapulars, and rump, are of a dusky black colour ; wings 
and coverts nearly of the same tinge. The breast, belly, and 
vent are of a dun mouse colour. The tail consists of twelve 
feathers, of which the two middle feathers project three inches 
beyond the rest, and taper at the point. 
Female . — The general appearance of the female is much the 
same as that of the male, but the breast and belly are rather of 
a leaden than of a mouse colour ; and in some individuals a 
line of yellowish-white nearly surrounds the neck. The two 
middle feathers of the tail are not quite so long as those of the 
male. 
The weight and dimensions of both are nearly the same. 
The length is twenty inches, and the breadth between the ex- 
tended wing three feet and a half. The weight is between 
fourteen and fifteen ounces. 
This bird may be called the Larus parasiticus niger. 
The following are the particulars of the white kind of Arctic 
gull. 
Milled The crown of the head, upper part of the body and 
tail, are bf a dusky black colour. The under part of the body, 
beginning at the breast, and continued to the tail, is pure white. 
The chin and throat mottled with white and mouse-colour. 
A white line surrounds the neck at its lower part. 
Female . — The female very nearly resembles the male, but 
while the under part of the body of the latter is altogether 
white, the vent of the female is dusky, inclining to black. The 
construction of the tail is the same as in the former species. 
The size and weight of both are nearly alike. The length 
is twenty-one inches, and the breadth three feet seven inches 
and a half. The weight is sixteen ounces. The white kind, 
therefore, are larger than the black. They are also less nume- 
rous, more shy, and not so bold as the other. 
To distinguish this latter species from the former, it may be 
called Larus parasiticus albus , or albi-venter . It would great- 
ly facilitate the recollection of the names of animals, as well as 
be more philosophical in itself, if, instead of deriving the appel- 
