148 THE DEVELOPMENT OF THE CHICK 
Fig. 83. — Five stages in the history of the neuromeres of the brain of the 
chick. (After Hill.) All figures drawn from preparations of the embryonic 
brain dissected out of the embryo. 
A. Neural groove in an embryo with 4 somites. Right profile view. x 44. 
B. Brain of a 7s embryo, 26 hours old. Dorsal view; the three anterior 
neuromeres are practically obliterated. x 44. 
C. Brain of 14s embryo. Dorsal view. x 44. The neuromeres have 
now disappeared in the mid-brain region. 
D. Right side of the brain of a chick embryo, 47 hours old. x 44. 
Ki. Right side of the brain of an embryo, 80 hours old. x 17. 
1-11, Neuromeres 1 to 11. III, V, VII, interneuromeric grooves. A't., 
toot of acustico-facialis (seventh and eighth cranial nerves). au. vs., Audi- 
tory pit. ep., Epiphysis. r., Groove between the tel- and diencephalon. 
s., Groove between the par- and synencephalon. Tr., Root of trigeminus. 
