174 
ANAS HYPERBOREA. 
*2o5> JyJS HYrERI}01lEA,-~-‘YOU'SQ OF THE SNOW GOOSE* 
WILSON, PLATE LXIX. FIG. V. 
The full pluraag-ed perfect male bird of this spec’^ 
has already been described in the preceding- artic'f! , 
and I now hazard a conjecture, founded ou the W*, 
examination I could make of the young bird, compar*''^, 
it with the descriptions of the different accounts, 1*'*. 
the whole of them have been taken from the vari^ 
individuals of the present, in a greater or lesser degf*' 
of approach to its true and perfect colours, &c. 
These birds pass along our coasts, and settle in 
rivers, every autumn ; among thirty or forty, there 
seldom more than six or eight pure white, or old bif“'] 
The rest vary so much, that no two are exactly alit^ 
yet all bear the most evident marks, in the particu' j 
structure of their bills, &c. of being the same ident*^/ 
species. A gradual change so great, as from a bird *' 
this colour to one of pure white, must necessai’*' I 
produce a number of varieties, or differences in - 
appearance of the plumage, but the form of the bill [ 
legs remains the same, and any peculiarity in cither >' 
the surest mean we have to detect a species under 
its various appearances. It is therefore to be regretir" 
that authors have paid so little attention to the singi'l'j 
conformation of the bill ; for neither that nor the inter"*^ 
peculiarities are at all mentioned. 
The length of the bird was twenty-eight incljj^, 
extent, four feet eight inches ; bill, gibbous at the si#'^' 
both above and below, exposing the teeth of the upPf 
and lower mandibles, and furnished with a nail ,, 
tip on both ; the whole being of a light reddish P'*rp j 
or pale hake, except the gibbosity, which is black, »■!, 
the two nails, which are of a pale light blue ; nostr ’ 
pervious, an oblong slit, placed nearly in the niidoj 
of the upper mandible; irides, dark brown; ’'’'*'‘’1 
head, and half of the neck, white ; rest of the 
