Warren Harmon Lewis 



527 



grafts of E. pahistris and E. sylvatica, and how dependent the lens is 

 for its origin upon the influence of the optic vesicle. 



Harrison (see footnote 4) has shown how perfect such unions may be 

 and how the lateral line sense organs starting from the head of E. syl- 

 vatica may grow quite normally into the tail of Eana palustris, which 

 has been grafted onto the E. sylvatica. 



Eleven other experiments of the series XII in which the embryos were 

 killed in from two to eleven days after the operation show the right eyes 

 deeply buried beneath the surface of the grafted-on ectoderm. In none 

 are there indications of lens formation. 



i.j,«— ZU«, 



oc- 



Fig. 35. ^^'«- 36- 



Fig. 34. Experiment XII51. Outline 7 days after operation, lateral view, ab, line be- 

 tween R. sylvatica and R. palustris. the right eye of R. palustris deeply buried, it ap- 

 proaches nearer the surface of the R. sylvatica ectoderm on the dorsal side. X 4 diameters. 

 Fig. 35. Experiment XIIsi. Section through the right eye of R. palustris. ab, points at 

 junction of ectoderm of R. palustris and R. sylvatica. a, near the middorsal line of R. 

 palustris. I, lens, oc, optic cup. X 45 diameters. 



Fig. 33. Experiment XII51. Enlarged part of Fig. 35. f, lens, oc, optic cup. X HO 

 diameters. 



The work of Colucci, Wolff, Muller and Fischel on the regeneration 

 of the lens from the edge of the iris might lead one to look for a similar 

 origin in some of the transplanted or deeply buried eyes in the various 

 experiments noted above, but with the exception of the one experiment, 

 DF33, there are no indications of such an origin. The many examples 

 of deeply buried eyes without lenses would lead to the conclusion that 



