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Charles R. Stockard 



Camera -lucida sketches of living embryos from MgClz solutions 



Fig. 3 A normal embryo of forty-two hours, the two optic vesicles present. 



Fig. 4 A typical cyclopean individual of forty-two hours. The single median eye(0. V.) is rep- 

 resented in circular outline. 



Fig. 5 An embryo of same age, twisted brain, no optic vehicle shown. 



Fig. 6 Normal seventy-two hour embryo. 



Fig. 7 Cyclops of same age. The eye, op.c, in ventro-median position. 



Fig. 8 Sixty-five hour embryo, two ventrally approximated optic cups. 



Fig. 9 Normal four day embryo — bilateral brain outhned. 



Fig. 10 Four day cyclops, large ventro-median eye and typically bilateral brain, op.c, the eye. 



Fig. II Four day cyclops with narrow tubular central nervous system. 



Figs. 12 and 13 Five day cyclops, narrow tubular brain with waist-like constrictions dividing them 

 into fore, mid and hind-brain regions. Ventro-median eye. 



Fig. 14 Five day cyclops with ventro-median eye and dorsally humped brain. 



