THE EYES OF THE BURROWING OWL 
822 
Seen from above, the relatively small pecten closely resembles a 
disarticulated, acuminate leaf, the stem representing the spinous 
projection immediately above the lowest terminal convolution. The 
light double folds of the marsupium slope backwards and cover most 
of the optic entrance; they meet above in a uniform, very narrow, 
slightly undulating crest whose posterior end projects half the height 
of the underlying coil well into the vitreous cavity. An extension 
upwards of the long axis of the disk cuts the retinal band at the 
junction of the inner and second fourth, making an infulapapillary 
angle of, perhaps, 40°. 
This interesting owl is especially subject, like other Strigiformes, 
to pathological variations in the fundus picture after confinement 
and domestication. Both Head and the writer examined a number 
of individuals that undoubtedly exhibited choroidal disease and 
other pathological changes. Rejecting these, the general color of 
the fundus of this species is found to be dull-orange, mottled and 
blotched in its upper half with deep orange-red. Choroidal vessels 
are plainly visible, covering all the lower part of the eyeground, just 
as in the Tawny Owl. The well-defined macular area is seen within 
the outer half of the fundus, a little above the upper extremity of 
the optic disk. It is distinguished from the surrounding choroid by 
a collection of minute pigment granules or dots with a bright, white 
spot in their center. 
The optic disk is white and of oblong shape, slightly rounded at 
the ends. From its edges run a few short nerve fibers that form a 
complete fringe about the visible papilla. 
The pecten is decidedly larger in proportion to bodily measure- 
ments than one finds it in most of the larger owls, especially larger 
than in the Tawny Owl. It extends well forward into the vitreous, 
and its lower half appears very massive and of a dark brown color. 
The pectinate convolutions are plainly seen and the anterior or 
upper half is more delicate in structure, being perforated where it 
joins the disk. Here it forms a dark network on the surface of the 
nervehead, where, also, a few red granules mingle with the chocolate- 
brown texture of the pecten. 
