ACUTE VISION IN VERTEBRATES. 495 



EXPLANATION OF PLATE XXVIII. 



Fig. 24. Human, age 4. Horizontal section through the center of fovea of 

 the right eye. The eye was enucleated during life and immersed at once in the 

 hardening fluid. Section 36;^ thick. X 32.3. 



Fig. 25. Human, adult. Horizontal section of right eye through center of 

 fovea. Eye was enucleated during life and subjected at once to the hardening 

 fluids. Section 36/^ thick. X 32.3. 



Fig. 26. Gorilla. Horizontal section of right eye through center of fovea. 

 The eye was about nine hours /i^j/ mortem and the apparent depth of fovea is due 

 to the folds of the retina in the macula. Section 36/i thick. X 32.3. 



Fig. 27. Gorilla. Vertical section through the center of the fovea and the 

 folds of the macula, showing the folds as they appear due to post moi-tem changes. 

 Section 36/i thick. X 32.3. 



Fig. 28. Robin (Merula migratoria). Horizontal section through center of the 

 fovea of right eye. Eye was subjected to hardening fluids immediately after death. 

 Section 24/^ thick. X 32.3. 



Fig. 29. Blue-Bird (Sialia sialis). Horizontal section through center of the 

 fovea of the left eye. Subjected to hardening fluids immediately after death. 

 Section iS^u thick. X 32.3. 



Fig. 30. Kinglet (Regulus satrapa). Horizontal section through center of 

 the fovea of the right eye. The head was subjected at once after death to hard- 

 ening fluids and sections afterwards made through whole head with eyes in situ. 

 This section includes not only the bottom of the fovea, but also some of the cells 

 of the area beyond. Section 24;U thick. X 32.3. 



Fig. 31. Snow-Bird (Junco hyemalis). Horizontal section through center of 

 the fovea of right eye. This eye was hardened by the injection method. The 

 retina in the region of the fovea floated off from the choroid. Section 36^ 

 thick. X 32.3. 



Fig. 32. Goose (Anser cinereus domesticus). Vertical section of right eye. 

 Across band-like area on the nasal side of the fovea about midway to the ora 

 serrata. The arrow points to the center of the area. Eye was subjected to hard- 

 ening fluids immediately after death. Section 36/4 thick. X 32.3. 



Fig. 33. Goose. Vertical section through the center of the fovea of right 

 eye. Section 1611 thick. X 32.3. 



Fig. 34. Goose. Vertical section of right eye across band-like area on the 

 temporal side of fovea about midway to ora serrata. The arrow points to the 

 center of the area. A fold in the section partly obscures the area. Secrion 36^ 

 thick. X 32.3. 



Fig. 35. Turkey (Meleagris gallopavo). Horizontal section through center 

 of the fovea of right eye. Eye was immersed at once after death in hardening 

 fluid. Section 36^ thick. X 32.3. 



Fig. 36. Guinea Hen (Numida pucherani). Horizontal section through center 

 of area of right eye. The eye was subjected to hardening fluids at once after 

 death. The arrow points to the center of the area where a very slight pitting may 

 be seen, which may possibly be called a fovea. Section 24;U thick. X 32.3. 



