Pirate I 
Fig. 1 External view of normal chick embryo after 74 hours of incubation. w, wing bud. 
Fig. 2 Cross-section through the brachial region of the embryo shownin Fig. 1. g, ganglion; m 
myotome; 7, end of nerve trunk; w, wing bud. 
Fig. 3 Cross-section through the brachial region of the embryo in Experiment 538. 
bi biceps 
ps pectoralis secundus 
pt pectoralis tertius 
ss supraspinatus 
ssp subscapularis 
cb r coraco-brachialis 
dt deltoides 
Id latissimus dorsi 
pmj pectoralis major ti teres et infraspinatus. 
Fig. 4 Cross-section through the brachial region of the embryo in Experiment 206. 
Fig. 5 Cross-section through the brachial region of the embryo in Experiment 225 
Fig. 6 Cross-section through the posterior part of the wing region in Experiment 179. 
