GALEUS 
From INSIDE 
lo 
Gian 
WR MAAN 
MAN 
Fic. 10.—Illustrations of the nictitating membrane in the various animals named, 
drawn from nature. The letter N indicates the membrane in each case. In man 
it is called the plica semilunarés, and is represented in the two lower drawings 
under this name. In the case of the shark (Ga/ews) the muscular mechanism is 
shown as dissected. 
