oa 
Instincts, Habits, and Adaptations 75 
it. In most flounders the eye seems to move over the surface 
of the head, before the dorsal fin, or across the axil of its first 
ray. In the tropical genus Platophrys the movement of the eye 
is most easily followed, as the species reach a larger size than 
do most flounders before the change takes place. The larva, 
while symmetrical, is in all cases transparent. 
In a recent study of the migration of the eye in the winter 
Fic. 57. 
Fies. 56, 57.—Larval stages of Platophrys podas, a flounder of the Mediterranean, 
showing the migration of the eye. (After Emery.) 
flounder (Pseudopleuronectes americanus) Mr. Stephen R. Wil- 
liams reaches the following conclusions: 
1. The young of Limanda ferruginea (the rusty dab) are 
probably in the larval stage at the same time as those of Pseu- 
dopleuronectes americanus (the winter flounder). 
2. The recently hatched fish are symmetrical, except for the 
relative positions of the two optic nerves. 
3. The first observed occurrence in preparation for meta- 
morphosis in P. americanus is the rapid resorption of the part 
of the supraorbital cartilage bar which lies in the path of the 
eye. 
4. Correlated with this is an increase in distance between 
