50 
SNOW OWL. 
where they are about two inches apart ; fore part of the 
crown, thickly marked with roundish black spots ; tail, crossed 
with bands of broad brownish spots; shafts of all the plumage, 
white ; bill and claws, as in the male, black ; third and fourth 
wing-quill the longest ; span of the foot, four inches. 
From the various individuals of these birds which I have 
examined, I have reason to believe that the male alone 
approaches nearly to white in his plumage, the female rarely 
or never. The bird from which the figure in the plate was 
drawn, was killed at Egg Harbour, New Jersey, in the month of 
December. The conformation of the eye of this bird forms a 
curious and interesting subject to the young anatomist. The 
globe of the eye is immoveably fixed in its socket, by a strong 
elastic hard cartilaginous case, in form of a truncated cone ; 
this case being closely covered with a skin, appears at first to 
be of one continued piece ; but, on removing the exterior 
membrane, it is found to be formed of fifteen pieces, placed 
like the staves of a cask, overlapping a little at the base, or 
narrow end, and seem as if capable of being enlarged or 
contracted, perhaps by the muscular membrane with which 
they are encased. In five other different species of Owls, which 
I have since examined, I found nearly the same conformation 
of this organ, and exactly the same number of staves. The 
eye being thus fixed, these birds, as they view different 
objects, are always obliged to turn the head ; and Nature has 
so excellently adapted their neck to this purpose, that they 
can, with ease, turn it round, without moving the body, in 
almost a complete circle.* 
* In prefixing the generic appellations to this curious family, I must at once 
confess my inability to do it in a manner satisfactory to myself. They have 
been yet comparatively unstudied ; and the organs of greatest importance have 
been seemingly most neglected. Neither my own collection, nor those 
accessible in Britain, contain sufficient materials to decide upon : I will, 
therefore, consider any attempt now to divide them in the words of Mr 
Swainson, “ as somewhat speculative, and certainly not warranted by any 
evidence that has yet been brought forward on the subject.” The names are 
applied, then, on the authority of ornithologists of high standing. 
This Owl, and some others, will form the genus Noctua of Savigny and 
