68 



THE FUNDUS OCULI OF BIRDS 



a few short opaque nerve fibres. The pecten 

 is chocolate brown, and in addition to its 

 massive appearance is much shorter than 

 the same organ in most of the birds examined. 

 All parts and all details of this pecten can be 

 viewed with the mirror without the least 

 difficulty. It is easy to see that it is fringed 

 all around with pointed tabs, that the central 

 portion or ridge is serrated and that it comes 

 well forward towards the lens. In examin- 

 ing the fundus with the ophthalmoscope 

 through the undilated pupil the pecten seems 

 to fill the pupillary area so that most of 

 the fundus is obscured and shows through 

 the fringe about the papilla as a light shines 

 through a grating. 



CARINATAE 



Galliformes 



Yarrell Curassow. Crax globosa. The 

 fundus appearances of this bird are depicted 

 as Plate VI, page 125, and are the result 

 of an examination of four eyes in two speci- 

 mens. The four backgrounds were found 

 to be identical in all respects. 



The eyeground is a dull, leaden gray 

 covered with tiny, white dots. There are 

 no visible choroidal vessels. 



The papilla appears as a long oval, whose 

 central zone is dull-orange mingled with 

 minute, dark-brown dots. It also presents 

 a marginal fringe of white. A few opaque 

 nerve fibres extend on either side of the 

 disc across the fundus, but for a short dis- 

 tance only. 



The pecten, of spiral form, is colored dark 

 chocolate-brown. It seems to taper quite 

 decidedly where it joins the disc, and looks 

 like the roots of a tree at its distal end, 

 where the rootlets bury themselves in the 

 disc. Just above the disc, some little dis- 

 tance to the nasal side of the pecten, is a 

 round, gray, softly outlined area near which 

 is seen a well-marked reflex of a pale blue- 

 green tone. 



Brush Turkey. Catheturus lathami. 

 Plate VII, page 127 depicts an ophthalmo- 

 scopic view of this species. 



The eyeground is dull, slaty gray, under- 

 lying numbers of fine, light-gray dots. These 

 dots are uniformly scattered over the fundus 

 except towards the nasal side. Here, on a 

 level with the superior end of the optic 

 nerve and in the direction of the macular 

 area, they are brilliant white, are closely 

 packed together and are devoid of a reflex- 

 ring. 



Extending from either side of the optic 

 disc and running at right angles to that 

 organ are a few, rather fine, semitranslu- 

 cent nerve fibres, which are lost towards 

 the periphery. 



The optic disc, whose upper end is shaped 

 like the sharp bow of a boat, appears to be 

 composed of a mass of brilliant, white, opaque 

 nerve fibres. 



The pecten, of the usual chocolate brown 

 color, is massive and somewhat club-shaped. 

 It extends well forward towards the lens 

 and tapers rapidly as it approaches the 

 superior end of the nerve. 



California Valley Quail. Lophortyx 

 californicus vallicola. (Figs. 110 and 79.) An 

 examination of this background with the 

 naked eye discloses no well-defined macular 

 region, at least not in this specimen; it may 

 be that in better preserved material a shallow 

 fovea can be isolated. The pecten presents 

 anteroposteriorly an elongated, acuminate 

 figure with 30 convolutions, or 15 folds, 

 regularly disposed on either side of a straight, 

 linear, median crest, that runs the whole 

 length of the upper aspect of the free border. 

 The convolutions are separated at several 

 points, especially near the middle, so that 

 glimpses of the dotted, whitish optic entrance 

 beneath may be seen. 



Harlequin Quail. Coturnix histrionica. 

 The remarkable fundus of this bird, viewed 

 with the ophthalmoscope, is portrayed as 

 Plate VIII, page 127, of this monograph. 

 The picture is the result of an examination 

 of several individuals, all exhibiting identical 

 eyegrounds. 



The general color of the ocular background 

 is light gray sprinkled with minute granules, 

 which give it the appearance of a rough 

 surface. This granular surface appears 



