ENPages
page_0046
as the nictitating membrane, a delicate translucent, partia[l] white, fold of the inner layer of the eyelids. This "winker" sweeps across the ball from the inner edge of the eye. Owls habitually sit in the day time with this curtain shading the eye from the glare of the sun, and doubtless the eg throws this same curtain across his eye, when soreing towards the sun. When not in action the "winker" lies curled up in the corner of the eye like a patterned window shade.
The pyramadalis muscel contracts and its tendon pulls the rictitating membrane over the eye, the harder this muscle pulls the harder quadratus pulls and thus the tendon does not obtrude on the optic nerve.
Birds have a lachrymal gland in each corner of each eye, inner and outer but they can not be said to cry.
The iris is commonly black or brown; red, yellow, blue, green and white are also found. The pupil of the Great-horned owl, range from the diameter of a finger ring down to that of a small pea.
page_0047
This page is not transcribed, please help transcribe this page
page_0049
Birds Ears No external ear is ordinarily present as a cortilagenous appendage, though owls at least have a considerable flap which over [his] the auditory apparatus. In place of the external ear we sometimes find a set of ear coverts, or ariculars.
The Respitory System of Birds No other animal are so thourg permeated with the atmosphere as are birds. In no others are the respitory functions so energetic and effectual. The lungs are not shut off by a diaphragm, but extend from the apex of the chest to the kidneys. They are divided into lobes as in mamals. nor do they hang freely with chest, but are fixed in the dorsal region of the general cavity, being also imbedded in the inner spaces of the ribs and [vertelrae]
A bird is literaly inflated with great recepticals of air and draws a remarkbly "long breathe" these recepticals vary greatly in extent and disposition being found in many or most, or all of the bones; in intermuscular spaces throughout the cellular tissue just beneath the [skin ed]
These substanteous cells are enormously
page_0050
This page is not transcribed, please help transcribe this page