EVIDENCES FROM MORPHOLOGY 147 
GALEUS 
From INSIDE 
Sea LION 
i 
i 
y 
THE EYEBALL 
REMOVED 
QRAy 
Fic. 19.—Illustrations of the nictitating membrane in the various animals 
named, drawn from nature. The letter N indicates the membrane in each case. 
In manit is called the plica semilunaris and is represented in the two lower drawings 
under this name. In the case of the shark (Galeus), the muscular membrane is 
shown as dissected. (From Romanes.) 
