THE FUNDUS APPEARANCES IN VARIOUS ORDERS OF BIRDS 107 



furnishes an exact view of the ophthalmo- 

 scopic appearances of the fundus oculi of this 

 species. It is of the left eye, erect image. 

 The general fundal coloration is pale gray, 

 with a dense mass of grayish white dots 

 permeating the entire background. 



Slightly above the upper termination of the 

 optic nerve, and towards the nasal side of the 

 pecten, is a well-defined, round, white area, 

 (the macula and fovea) much larger than the 

 small spots that cover the whole of the sur- 

 rounding, duller eyeground. This white area 

 is inclosed by a brilliant, bluish-green circle, 

 which appears more prominent and iridescent 

 in nature than is depicted in the drawing. 



Little can be seen of the optic papilla be- 

 cause it is almost entirely obscured by the 

 pecten. However, it is long and narrow, with 

 an irregular outline. 



On the nasal side of the nerve-head are a 

 few short, orange-red, choroidal blood-vessels 

 with a few dots of pigment, like pepper grains, 

 sprinkled between them. Extending from 

 both margins of the optic disc across the 

 fundus to the periphery, are numerous fine, 

 opaque nerve fibres, the upper ones (on the 

 nasal side), terminating at the macular area. 



The pecten, red-brown in color, long and 

 narrow, appears to be twisted on itself like a 

 rope or a corkscrew. Its inferior end extends 

 beyond that part of the eyeground shown in 

 the picture, but it probably comes well for- 

 ward towards the posterior surface of the 

 lens. 



English Nightingale. Aedon megaryn- 

 cha. The ophthalmoscopic appearances of 

 this species is almost identical with those of 

 the Wheatear (see Plate LII, page 171), ex- 

 cept that in Saxicola the macular region is 

 not so well defined. 



California Shrike. Lanius ludovicianus 

 gambeli. (Figs. 107 and 141; macroscopic 

 view). 



There are two macular regions in the fundus 

 of this bird, similar in every detail to the same 

 areae in the Bluebird. 



The optic papilla is, however, longer and 

 somewhat narrower in Lanius, and the more 

 extensive pecten exhibits folds joined along 

 its free border by a rounded crest that from 



above takes on the shape of a carrot. The 

 major axis of the long ovoid disc projected 

 until it meets a line crossing the floor of the 

 concave fundus and joining the two foveolse 

 would subtend an (infulapapillary) angle of 

 about 110°. 



Passeriformes. B. Alaudidae 



European Titlark. Anthus pratensis. A 

 healthy adult male individual of this species, 

 about three months in captivity, obtained 

 from a dealer, was examined by the writer in 

 the laboratory of St. Luke's hospital. The 

 pupils were unaffected by one drop of a 1% 

 sol. of atropia instilled 48 hours previously. 

 The bird was strongly hyperopic and very 

 slightly (about 0.33 D.) astigmatic, the skia- 

 scope showing 3.50 D. of HAS in each eye. 



The ophthalmoscopic examination revealed 

 no opacities in the ocular media. 



The pecten is of the usual black-brown 

 color; it is large and spiral, filling the whole 

 pupillary area when examined with the mir- 

 ror, and almost entirely obscures the outline 

 of the optic papilla from which it springs. 



The background is of a fine, pepper-and- 

 salt character with a very few opaque nerve 

 fibres radiating from the disk. Scattered 

 over the field are many fine sparkling points 

 like minute grains of cholesterine. These 

 are also to be found in the macular region, 

 which is definitely outlined directly in the 

 axis of vision and covers a space about J^ of 

 a disc-length. The mirror does not show a 

 second area of acute vision. 



Passeriformes. B. Fringillidce 



British Linnet. Linota cannabina. The 

 indirect ophthalmoscopic examination of an 

 imported individual, in captivity a year or 

 less, shows a pecten that obscures a view of 

 the fundus details, but the prevailing color 

 of the eyeground is readily seen to be a beauti- 

 ful, light, gray-blue beset with whitish dots. 



British Goldfinch. Carduelis elegans. 

 The fundus of this bird as seen by the indirect 

 method — it was extremely difficult and un- 

 satisfactory to make an ophthalmoscopic 

 examination by the erect image — showed an 

 eyeground that resembles that of the Linnet 



