SNOWY OWL. 193 



is almost free from dark markings. The variation, as in 

 the case of the Greenland Falcon, seems to be purely 

 individual, for specimens of either sex may be obtained 

 representing its extreme limits, while examples kept in 

 confinement exhibit no perceptible change consequent upon 

 age. The dark marks when present are situated towards 

 the end of the feather ; and on the under surface are semi- 

 lunar in shape, while those on the back and wings are more 

 linear. The feathers forming the incomplete 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 partially hidden by 

 feathers, and the latter 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. 



The vignette below represents the crystalline lens and the 

 bony ring of the eye in this bird, which may be compared 

 with those of the Eagle before figured (page 19). 



Prof. Nilsson has incontestably shewn that the Strix 

 scandiaca of Linnaeus, though originally figured and de- 

 scribed by error as a tufted Owl, was founded upon an 

 example of this species, and the trivial name of his iS'. 

 nyctea, which no one ever doubted to be the Snowy Owl, 

 having been used for the genus by Stephens, it thus seems 

 only proper to recur to the former as the distinctive appel- 

 lation of this bird. 



VOL. T. c c 



