CLASSIFICATION OF THE OCULAR FUNDI OF BIRDS 



113 



nocturnal habits. Among them are the Bra- 

 zilian Boatbill (Plate XXII), Kakapo (Plate 

 XL), and the Barn Owl (Plate XXXVIII). 



(d) Vascular fundi whose general colora- 

 tion is brown, brownish or russet are also fairly 

 common. The White-bellied Sea Eagle (Plate 

 XXXIV), Gila Woodpecker (Plate XL VII), 

 Laughing Kingfisher (Plate XLII), Little 

 Bustard (Plate XXXVI), Raven (Plate 

 LVIII), Stone Plover (Plate XVII), Great 

 Blackbacked Gull (Plate XVI), Blue Snow 

 Goose (Plate XXVII) and the Chimney 

 Swallow (Plate L) are among them. 



(e) Bicolored or multicolored vascular fundi 

 are commoner than those classed under A (e). 

 The vascular eyeground of the Martineta 

 Tinamou (Plate V) is brownish below and 

 light gray above; its color scheme reminds 

 one of the ocular background (when seen 

 ophthalmoscopically) of some mammalian 

 fundi. The Australian Pelican (Plate XXX) 

 has a fundus oculi which is russet below 

 gradually shading to grayish above. The 

 eyeground of the Kagu (Plate XVIII) is also 

 reminiscent of mammalian color mixtures; the 

 lower half of the background is a well-marked 

 red-brown dotted with black pigment, while 



the upper segment is a sky blue. The lower 

 two-thirds of the fundus oculi of the Brazilian 

 Seriema (Plate XIX) is brownish, the upper 

 third slate-blue. The Bald Eagle (Plate 

 XXXIII) has also a mixed fundal coloration; 

 being dull red-brown below and mottled gray 

 above. Finally, the eye of the nocturnal 

 Nightjar (Plate XLIV) mimics to some extent 

 the fundal color distribution in the background 

 of certain of the night-prowling mammalian 

 Carnivores, being dark orange-red below and 

 light orange above. 



In the above classification the colored dots 

 that besprinkle the fundus picture of practically 

 all Birds (and represent, probably, the colored 

 droplets of the retina) are not considered. 

 However, both directly and by contrast they 

 greatly modify the color impression made 

 upon the observer, and especially when they 

 are large and numerous, influence the general 

 chromatic effect. In some instances, their 

 number and distribution are such as to deter- 

 mine the verdict of a first glance, and the 

 observer must be on his guard not to mistake 

 these accessory pigment points for the solid 

 background of color which one finds in all 

 avian fundi. 



