No. 391.] OBSERVATIONS ON OWLS. 565 
are more than two present in the same pellet, and pellets of 
this nature are considerably longer than usual, though of the 
ordinary diameter. The pellet, when the object eaten is a mam- 
mal or bird, is composed of a tightly welded mass of bones and 
hairs, or feathers. In the stomach of the owl the food mass 
must be subjected to a vigorous churning process, for onl 
such a process could serve to explain the close welding of the 
materials in the ejected pellet. In a pellet there are no empty 
spaces, but the hairs or feathers fill tightly all the spaces 
between the bones, and are jammed into all grooves and foram- 
ina of the latter, the pellet, when fresh, being so compact 
that it cannot be roughly torn apart without breaking the bones 
contained in it. The skulls of mice are usually found crushed 
in the occipital region (the weakest portion), usually more or 
less intact anterior to the frontal; out of 570 skulls of the 
meadow mouse taken by me from pellets, only some fifty had the 
occipital region uninjured and attached to the rest of the skull; 
when several mice are contained in the same pellet, the state 
of preservation of the skulls is better than usual. It is truly 
remarkable how the hair is worked, by the churning process of 
the owl’s stomach, into all cavities of the skull. There is 
always a tight wedge of hair in the preorbital foramen, in the 
foramen lacerum, in the ear and nasal cavities, as well as in 
smaller apertures. When the occipital region of the skull is 
crushed, the cranial cavity contains a tight wad of hair; and 
in a few skulls which remained intact the whole cranial cavity 
was densely packed with hair which had been forced through 
the foramen magnum! The lower jaws are usually well pre- 
served (though their angular and coronary processes are fre- 
quently broken), and teeth are well preserved. Of the other 
bones of the mouse’s skeleton contained in a pellet, it is strange 
that the slender and delicate ulnz and radii are usually intact ; 
the proximal end of the humerus is usually dislocated; the 
femora, tibiz, ilia, vertebræ, and small bones of the hand and 
foot are usually uninjured, while the ribs, scapulæ, and fibulz 
are usually broken. The less strongly built skulls of shrews 
and birds are considerably more crushed. As MacGillivray 
noted in 1836, the linings of birds’ gizzards are disgorged intact 
