PLATE V. 
Fig. 35. Outline sketch of seventh operative stage (XIV). XxX 6% diam- 
eters. 
Fia. 36. Section through eye region of an embryo of above stage (XIV). 
The lens-vesicle is but slightly adherent to the ectoderm. X 45 diameters. 
Fic. 37. Experiment XIV;,. Section through right lens, 5 days after the 
almost complete extirpation of the optic cup. The lens measures only about 
150. in diameter. The lens-fibers appear rather healthy, but the medial 
pole has disappeared, owing to the complete layer of surrounding epithelium. 
x 180 diameters. 
Fig. 38. Experiment XIV,. Section through right lens of an embryo 
killed 8 days after removal of the optic cup. The lens is completely sur- 
rounded by a single layer of columnar epithelium, and measures about 
160 « in diameter. The lens-fibers are degenerating, but an indication of the 
medial pole still remains. (Contrast normal lens, Fig. 39). X 180 diam- 
eters. 
Fic. 39. Experiment XIV,. Section through left normal lens of above 
8-day embryo. The lens measures about 180 in diameter. X 180 diameters. 
Fic. 40. Experiment XIV,,. Section through right lens, 10 days after 
removal of the influencing optic cup. It measures about 160 ~ in diameter, 
being considerably smaller than the normal lens 190 «in diameter, and shows 
no medial pole. X 180 diameters. 
Fig. 41. Experiment XIV,,. Section through right lens of an embryo 
killed 30 days after the complete extirpation of the optic cup. The lens 
measures about 200 w in diameter, while the normal lens of the opposite 
side is about 220 . in diameter. It shows marked retardation in growth and 
differentiation, and is completely surrounded by a thin layer of epithelium, 
containing within a degenerating and vacuolated mass of lens-fiber material. 
(For contrast to left normal lens, see Fig. 9). X 180 diameters. 
