88 



THE FUNDUS OCULI OF BIRDS 



the temporal border of the field. Two lines 

 of pigment dots — the one at the nasal end 

 more plainly marked and each as long as 

 the disc — divide the terminals of the band 

 into two narrow spaces. The lower margin 

 of the band is drawn with numerous minute 

 pigment grains that are sparsely supplied 

 to the upper border except at its nasal end. 

 A third line of pigment, deeper in color than 

 the other two, and about as long as the 

 papilla is wide, indicates the middle point 

 of the band somewhat nearer its temporal 

 end. At this point the band becomes slight- 

 ly broader, especially below. In the centre 

 of this shortest line the pigmentation is 

 somewhat pronounced, but an outline of the 

 ordinary slit-like fovea within a retinal band 

 is not here well developed. 



An extension of the long diameter of the 

 papilla to meet the lower border of the retinal 

 band, makes with it an infulapapillary angle 



of 65°. 



Pelecaniformes 



Cormorant. Phalacrocorax carbo. The 

 fundus view shown in Plate XXVIII, page 

 147, of this work, represents the ophthalmo- 

 scopic examination of eight eyes of four indi- 

 viduals. Two were tame birds, the others 

 were freshly caught, but their eyegrounds were 

 identical. The drawing presents the appear- 

 ances in the left eye by the direct image. 



The fundus oculi is mostly of a slate- 

 gray color, uniformly sprinkled with numer- 

 ous, minute white dots, closely packed 

 together. Running chiefly parallel with the 

 long axis of the optic disc are several rather 

 straight, orange-red choroidal capillaries, 

 that extend the whole length of the papilla 

 and beyond its inferior extremity. 



The macular area is seen a little above the 

 upper end of the optic disc and on the nasal 

 side of the nerve. The fovea appears as a 

 reflex image of a few short, bright, white lines 

 surrounded by a narrow and similar ring. 



The optic disc gives the impression that 

 it is composed of a mass of very white, 

 cotton-like fibres, disposed as a fringe all 

 about the papillary margin. The central 

 area of the disc, especially on each side of 

 the root of the pecten is orange-red, 



stippled with minute, brown pigment 

 grains. Perpendicular to the papillary mar- 

 gins are a few short, fine opaque nerve 

 fibres, that run towards and are finally lost 

 in the peripheral eyeground. 



The pecten is rather long and of the usual 

 chocolate-brown tint; it is much narrower 

 than usual on the upper half of the disc, 

 and comes well forward into the vitreous 

 humor, extending behind the margin of the 

 pupil. 



Fallarone Cormorant. Phalacrocorax 

 dilophus albociliatus. An adult individual of 

 this species (while dying) was examined 

 by the writer in an open boat in San Diego 

 Bay, California. An ophthalmoscopic view 

 was obtained under these difficulties, and 

 is consequently incomplete. However, the 

 writer saw through dilated pupils that the 

 fundus was gray-black and uniformly dotted 

 throughout. The pecten was easily seen, 

 but not well enough to count or accurately 

 describe the arrangement of its plications. 



Brandt Cormorant. Phalacrocorax pe- 

 nicillatus. (Figs. 95 and 130.) This fundus 

 oculi, when viewed with the naked eye, in pre- 

 pared specimens, shows a broad, gray band 

 depicted in the black and white drawing as 

 extending in a rather oblique direction from 

 the nasal periphery of the field to a point im- 

 mediately above the superior end of the pa- 

 pilla. Here, just before it terminates, the 

 band widens and develops into an oval area 

 with a large central, black dot, crowned by 

 minute and scattered pigment grains. This 

 macular area is located about the width of the 

 minor axis of the optic disc from the upper ex- 

 tremity of the latter. 



[In the temporal margin of the black-and- 

 white drawing is a slit-like mark; this is not a 

 second fovea but an artefact fold in the retina.] 



The pecten presents a broad, and rather 

 long, pointed oval, with its blunt extremity 

 below. It is composed of 32 convolutions 

 whose free margins are united above in a keel, 

 and whose wide and thicker posterior fourth 

 covers nine equally long double coils. It 

 then slopes to the superior pointed extremity 

 of the disc, having joined, above, the remaining 

 nine unequally short coils. 



