SNOWY OWL. 145 
marks becoming smaller and smaller every succeeding year, 
until in very old individuals from high northern latitudes 
the whole plumage becomes pure white, without any spots 
whatever. The brown mark when present is situated 
towards the end of the feather bearing it; and upon the 
feathers of the under surface these markings are semilunar 
in shape, while those on the feathers covering the back and 
wings are more linear. The feathers forming the incom- 
plete facial disk, those of the upper part of the breast, and 
also the downy feathers defending the legs and toes, are 
pure white: the beak and claws are black; both are par- 
tially hidden by feathers; the latter are long, curved, and 
very sharp. The irides are bright orange yellow. The 
whole length of the Snowy Owl is from twenty-two to 
twenty-seven inches, the difference depending on the sex: 
the females are much the larger of the two. M. Tem- 
minck says the young birds are covered with brown down, 
and their first feathers are also light brown. 
The vignette below represents the crystalline lens and 
the bony ring of the eye in this bird, which may be com- 
pared with those of the Eagle at page 19, and both are 
referred to at page 15. 
VOL. I. L 
