Warren Harmon Lewis 



525 



of the latter. Here between this corner of the optic cup and a small 

 skin depression is a lens about 90 micro mm. in diameter, while the 

 normal left lens is 160 micro mm. in diameter. The abnormally placed 

 lens on the right side is not only smaller but is less differentiated than 

 the left one. 



Fig. 31. Fig. 33. 



Fig. 31. Experiment Xlg,,. Outline of tadpole drawn 8 days after the operation, ah, line 

 at junction of Kana sylvatiea and R. palustris. oc, optic cup. X i diameters. 



Fig. 33. Experiment XI;4. Outline 11 days after the operation. The right eye of E. 

 palustris is seen beneath the abdomen of R. sylvatiea. X 4 diameters. 



V«-vA«^Zi'«-°.' 



afijU'yy^^ 



Fig. 33. Experiment XI74. Section through the right eye of R. palustris. X 30 diameters. 



Experiment XI^^. 



As in the other experiments of series XI, the head end of E. sylvatiea 

 was grafted on over the right optic vesicle and structures about it of 

 E. palustris. In this experiment, however, the ventral surface of E. 

 sylvatiea faces in the same direction as the dorsal surface of E. palustris 

 see Fig. 32. A few days after the operation the right eye of E. palus- 

 tris became visible beneath the skin of the ventral surface of the abdo- 

 men of E. sylvatiea near its junction with E. palustris. Eleven days 

 after the operation the tadpole was killed. The sections show a well- 

 developed optic cup with a large, irregular lens, see Fig. 33. The 



