1900.] SHUFELDT—OSTEOLOGY OF THE STRIGES. 681. 
The femur in Strix fratincola appears to be pneumatic. All 
Owls appear to be supplied with a large patella at the knee. 
I shall now proceed to give a few selected extracts from my 
memoir on Sfeotyto cunicularia hypogea, as 1 said I would do in 
the Introduction to the present memoir. A superficial examination 
of askeleton of Seozyzo is quite sufficient to convince us that its 
affinities are with the bubonine Owls rather than with the genus 
Strix. We will not then have to especially dwell upon this point. 
Essentially, the characters of the skull and mandible of Speotyto 
are briefly as follows: 
Owing to its delicate structure, it is a skull of extreme lightness ; 
and as to form, its greatest width lacks but little of its being equal 
to its median longitudinal diameter. Vertically it is of moderate 
height, while the cranial vault externally is markedly smooth and 
rounded in the parietal and adjacent regions. The septum marium 
is complete, the external osseous nostrils being somewhat rounded 
ellipses in outline. Either lacrymal bone is free, and grooved 
upon its outer aspect for the lacrymal duct. Superiorly, we are to 
note in the frontal region that the skull is inclined to be narrow 
between the upper orbital margins; and the supraorbital processes, 
thrown outward and backward on either side by a frontal, are of 
spiculaform proportions. ‘The thin interorbital plate or partition 
may, and usually does, show one small central vacuity in it. The 
nerve foramina are small and generally round in outline. Pars 
plana is meagrely developed, and presents the characters of the 
bubonine Owls generally. A quadrato-jugal bar is stout, and is 
peculiar in that upon its superior aspect, at the junction of middle 
and posterior thirds, it sends upward a transversely compressed 
triangular process, that also exists as a character in the skulls of 
Surnia and the Pygmy Owls among American species now at my 
hand.  Postfrontal processes are broad and conspicuous, while a 
squamosal bone forms a great shell-like bulla that arches forward as 
a shield to the external auditory aperture. The antero-superior 
angle of this bulla, upon either side, fuses with the edge of the 
postfrontal at the orbital periphery, thus creating a small foramen 
there, which in the living bird transmits the tendon of the tem- 
poral muscle. The skull of Sfeotyfo is symmetrical. Above the 
foramen magnum a well-marked supraoccipital eminence is seen, 
which is pierced mesially by a small and usually circular vacuity. 
