MODIFICATION OF DEVELOPMENT IN THE FROG 487 
Figures 7 to 9 illustrate two embryos from the same lot of eggs, but 
exposed seventy-six hours to the solution and returned to water for 
twenty hours. Differential inhibition is more marked. Many of the 
embryos approach an anencephalic condition, and the bilateral sense 
organs of the head are much reduced or are not apparent at all. The 
Figs. 39 to 46 Differential inhibition. 39, dorsal, 40, 41, 42, lateral views ot 
four embryos after exposure to m/10.62 LiCl. Eggs unsegmented when placed 
in the solution. Treatment: 39, 40, 48 hours in LiCl + 28 hours in water; 41, 42, 
48 hours in LiCl + 73 hours in water. Exp. IV 22. y.p., yolk plug; t, tail; v.s., 
ventral sucker. 43, 44, lateral views of two embryos and, 45, lateral, 46, ventral 
view of a spina bifida embryo from same experiment as those shown in figures 39 
to 42, but after an exposure of 48 hours in LiCl + 83 hours in water. The em- 
bryos 43 to 46 show some differential recovery. 
