420 ROSS G. HARRISON 
The third and fourth digits appear successively on the ulnar 
(dorsal) border of the hand, first as nodules which slowly elon- 
Figs. 4to 9 Normal embryos of A. punctatum, showing form and posture of 
the developing fore limb. Description in text. X 10. 
gate, the fourth being considerably behind the third in its de- 
velopment (fig. 9). Viewed from above, the arm at this time is 
