No. 3-] ACUTE VISION IN VERTEBRATES. 493 



EXPLANATION OF PLATE XXVII. 



Fig. I. Human, left eye, \, showing nerve entrance {N), blood-vessels, and 

 macula and fovea (A F). 



Fig. 2. Gorilla, left eye, \. N, nerve entrance ; A F, area and fovea. 



Fig. 3. Dog (Canis familiaris), left eye, \. Shows nerve entrance (.A^) and 

 blood-vessels which were injected. 



Fig. 4. Cat (Felis catus domesticus), left eye, \. N, nerve entrance ; Ab, 

 white, band-like region, which appears as an area. The blood-vessels were in- 

 jected. 



Fig. 5. Fox (Vulpes vulpes), left eye, \. N, nerve entrance ; Ab, band-like 

 area. Blood-vessels were not injected. 



Fig. 6. Cow (Bos taurus domesticus), left eye, \. N, nerve entrance ; Ab, 

 band-like area. 



Fig. 7. Horse (Equus caballus), left eye, |. vV, nerve entrance; .4(5, band- 

 like area. 



Fig. 8. Sheep (Ovis avies), left eye, \. N, nerve entrance ; Ab, band-like 

 area. Blood-vessels were injected. 



Fig. 9. Pig (Sus domesticus), left eye, \. N, nerve entrance ; Ab, band-like 

 area. 



Fig. 10. Barred Owl (Syrnium nebulosum), left eye, \. N, nerve entrance ; 

 P, pecten ; A F, area and fovea. 



Fig. II. Red-Tailed Buzzard (Buteo borealis), left eye, \. N, nerve entrance ; 

 P, pecten; Ft, At, fovea and area temporalis; Fn, An, fovea and area nasalis; 

 Ab, band-like area. 



Fig. 12. Tern (Sterna hirundo), left eye, \. N, nerve entrance ; P, pecten ; 

 Ft, At, fovea and area temporalis ; Fn, An, fovea and area nasalis ; Ab, band-like 

 area. A dark line extending along the band-like area corresponds to Chievitz's 

 trough-like fovea. In cross sections no such fovea is found. 



Fig. 13. Rabbit (Lepus sylvaticus), left eye, \. N, nerve entrance; Ab, band- 

 like area. The blood-vessels were injected. 



Fig. 14. Fox Squirrel (Sciurus niger), left eye, -J-. N, nerve entrance; Ab, 

 area not visible to the naked eye. 



Fig. 15. Horned Toad (Phrynosoma cornutum), left eye, \. N, nerve en- 

 trance ; P, conical pecten; F, fovea; Ab, band-like area. 



Fig. 16. Turtle (Chelopus insculptus), left eye, \. N, nerve entrance ; A, 

 area, not visible to the naked eye ; Bv, an apparent rudimentary blood-vessel 

 which was injected. 



Fig. 17. Robin (Merula migratoria), left eye, \. N, nerve entrance; P, 

 pecten ; A F, area and fovea. 



Fig. 18. Frog (Rana catesbiana), left eye, \. N, nerve entrance; Ab, band- 

 like area, not visible to the naked eye. 



Fig. 19. Sparrow Hawk (Falco sparverius), left eye, \. N, nerve entrance; 

 P, pecten ; Ait, Fn, area and fovea nasalis ; At, Ft, area and fovea temporalis ; 

 Ab, band-like area. 



Fig. 20. Ring-Neck Plover (.(Egialitis semipalmata), left eye, \. N, nerve en- 

 trance ; P, pecten ; A F, area and fovea ; Ab, band-like area. 



