96 



THE FUNDUS OCULI OF BIRDS 



of the whitish nerve head, which is dotted 

 with very small pigment granules. 



The ophthalmoscopic appearances of the left 

 eye of Cacatua galerita, erect image, are por- 

 trayed in Plate XLI, page 161. The back- 

 ground is of a fairly uniform, light grayish-blue 

 color, sprinkled with minute white dots that 

 are interspersed with many less numerous 

 but somewhat larger dark gray deposits. 

 The macular area, at the upper-inner quad- 

 rant, is an irregularly round, light brownish 

 area whose diameter is half the disc length. 

 It is not, as in many Birds, surrounded and 

 denned by an outer ring; the periphery fades 

 into the surrounding gray of the fundus. The 

 upper sixth of the long, pointed papilla is 

 distinctly visible where it is not covered by 

 the indented pecten, whose twelve double folds 

 have a corkscrew termination above. Por- 

 tions of the disc borders can be seen from 

 above through the plications, except at its 

 posterior terminal where the dark-brown mass 

 entirely covers it. Faint, whitish lines of 

 opaque nerve fibres extend from the margins 

 of the upper half of the disc a short distance 

 across the centre of the eyeground. 



Orange-winged Parrot. Chrysotis ama- 

 zona. Plate XXXIX, page 159, represents 

 the ophthalmoscopic appearances in the right 

 eye of this species. The dominant color of 

 the eyeground is deep gray tinted with buff. 

 The lower sectors and the peripheral zone 

 of the fundus are suffused with pink, the 

 background generally being punctuated with 

 minute, dull-yellow dots. 



The macular area is situated towards the 

 nasal side of the disc, a little above the 

 end of the pecten. It is slightly depressed 

 and enclosed by a rather bright but pale-green 

 reflex-ring. Extending from the circum- 

 ference of this circle, slightly above as well as 

 below, are a few translucent fibres, pale 

 green in tone; and at its centre is a dark- 

 gray dot or depression, with a small, faint 

 halo extending from its upper edge. 



The optic nerve-head looks as if it were 

 composed of coarse, white, opaque fibres, 

 which form a fringe all around the deeply- 

 colored pecten. The papilla is long and 

 boat-shaped, and its outlines can be traced 



the whole length of the pecten. Many fine, 

 gray, opaque nerve fibres extend from the 

 margins of the papilla, cross the background 

 of the eye and are eventually lost in the 

 fundal tissues. 



The dark-brown pecten, seen from above, 

 has a spiral form, with a tag or tail-piece at 

 the upper end. A lateral view shows it to 

 be plicated, like a fan. It stands well forward 

 towards the lens. 



The light reflected into the eye from the 

 ophthalmoscopic mirror does not appear to 

 disturb specimens of the species at all, 

 unless it is concentrated on the macular 

 region. 



White-fronted Cuban Contjre. (?) 

 Conurus ridgway. The writer examined with 

 the ophthalmoscope the fundi of an individual 

 four years old that had been an inmate of 

 Bronx Park for three months. Neither a 

 one-fifth of one per cent solution of sulphate 

 of atropia nor a homatrophine and cocaine 

 mixture had any effect on the size or motility 

 of the pupil. 



The eyeground was generally reddish- 

 gray; the pecten was large, convoluted and 

 extended well into the vitreous cavity and 

 approached the posterior lens surface. There 

 was no well-defined macular region. The op- 

 tic entrance was almost covered, and a view 

 of it obscured, by the base of the pecten. 



J£akapo. Owl-Parrot. (New Zealand.) 

 Stringops habroptilus. In July, 1914, the 

 writer examined the single specimen then in 

 the gardens of the Zoological Society at 

 Regent's Park, London. The bird had, at 

 that date, been in captivity two years, and 

 seemed dazed when exposed either to bright 

 natural or artificial light. The keeper reported 

 that the bird is very quiet during the daytime 

 but digs in the sand of his box at night. The 

 lids have no cilia-like protection — only scat- 

 tered plumules on the otherwise naked lids. 

 He has large pupils and a dark brown iris. 



The red-brown fundus is fairly easily seen 

 with the ophthalmoscope without using any 

 mydriatic. The frontal position of the eyes 

 (found in all Strigiformes and to which 

 order the writer believes this species right- 

 fully belongs) is marked in this animal, and 



