MODIFICATION OF DEVELOPMENT IN THE FROG 483 
37 
Figs. 30 to 38 Differential acceleration. n/5000 HCl. Eggs two to four-cell 
stages when placed in the solution. 30, embryo after 60 hours in HCl, dorsal 
view; 31, controlat60 hours. 32, ventral and, 33, lateral view of one embryo after 
96 hours in HCl; 34, lateral view of control at 96 hours. 37, lateral and, 38, 
ventral view of head of one embryo after 6 days in HCl; 35, control, lateral view 
and, 36, ventral view of head, at6 days. a, anterior; m, mouth; md., medullary 
plate; 0, olfactory pit; v.s., ventral suckers; y.p., yolk plug. 30 to 35, Exp. HCl- 
C'.1; 35-38, Hzp. HCI-C.5. 
