21 
Ihcie aie few traces of chorioidal vessels here; probably we look at 
onl\ the translucent retina against the underlying chorioidal pig¬ 
ment. The optic disk is a long, whitish, ovoid figure surrounded bv 
the reddish chorioidal vessels. Springing from the whole length of 
the papilla and almost covering it is the pecten. Seen with the 
ophthalmoscope this organ presents the appearance seen in the pic¬ 
ture a smooth, black, corrugated, grub-like body slightly pointed at 
the papillary end. Viewed laterally the owl’s pecten closely re¬ 
sembles the dorsal view of a partially clenched hand. 
Lelow both papilla and macula is a rather large area, abundantly 
supplied with large chorioidal vessels, between which are masses of 
pigment. The nerve-head occupies the center of a smaller, much 
lighter, yellow field. On the whole, this nocturnal bird of prey 
Fig. S.—Postmortem and diagrammatic view of tlie double maculae, double 
fovea and third visual area of the Red-tailed Buzzard (Buteo borealis). N, optic 
nerve entrance; P. pecten ; Ft, At, fovea temporalis and area temporalis; Fn, 
An, fovea and area nasalis ; Ah, band-like area. (Slonaker.) 
shows a background such as we would expect from what we know 
of the fundi in mammals of similar habits. The refraction of this 
owl is about 3 diopters of simple hypermetropia. 
The Cape Eagle Owl (Bubo Capensis ) has, in half-lights, large 
round pupils. ITe shows, with the ophthalmoscope, the same red¬ 
dish background, the oval optic nerve and the pepper and salt area 
about the disk-like macular region seen in the Tawny Owl. In one 
specimen that had lived in the London Zoological Gardens three 
years, the refraction (as determined by the skiascope) was only 
-f- 2 "D., and I found several well-defined, pigmented, chorioiditic 
exudates in each eye. In the chorioid. around at least three of these 
spots, there was distinct evidence of absorption of the epithelium. 
