29 Hours 30 Hours 32 Hours 
ay (9 somites) B. (10 somites) C. 2 somites) 
D. Ges E 40 Hours FE. 42 Hours 
* (20 somites) 
44 Hours 
(22 somites) 
47 Hours 
(25 somites) 
G. Vel 
Fig.1, A toL Camera outl 
embryos, showing for each sta 
I . ie Liam 
ines (X 15) of cephalic and cardiac regions of chick 
ge studied the relations of the heart to neighboring 
378 
