170 THE TARPON 



In the light of the early morning and evening as the tarpon 

 jumps from the water in its terrific struggles the eye is said to 

 have a baleful glare that strikes terror to the heart of a timid 

 observer but which is wholly out of proportion to his actual 

 menace because the sight of the great creature in its native 

 element is poor and totally useless in our atmosphere. The 

 reason of this is a quality of fluorescence which the huge lens 

 possesses. The ultra violet rays which are almost if not com- 

 pletely invisible to our eyes, are still quite abundant in the 

 twilight and striking the lens through the large round pupil, 

 they cause it to sliine with a luminescent glow. The eyeball is 

 flattened both on the corneal and the posterior side. The 

 choroid gland between the retina and the sclera is covered 

 with flat plates of a highly reflecting substance called 

 "guarin.'" This catches the remaining rays of daylight which 

 are shot back in scintillating gleams. The reflection of the 

 shining cornea and of the glittering silvery surface of the iris 

 together with the excitement of a struggle from a small boat 

 on the ocean in the dimness of early morning, gives to the eye 

 of the creature a malevolence it is difficult to realize. 



The tarpon is a prototype of the prehistoric forms of which 

 fossil remains are still in existence. These date back to the car- 

 boniferous era and in the tarpon the characteristics of these 

 earlier forms are found. 



The eye of the tarpon has never as far as the writer can 

 learn been intensively studied and only an outline of its gross 

 anatomic features can be presented here. 



The eye of the tarpon is protected by veritable armor plates 

 in the large, heavy enamelled scales closely fitting around the 

 orbit. These are detached only with great difficulty. The 

 structure of the eye itself is dense and firm and calculated to 

 resist the great pressure of the deeper water. The integument 

 of the head forms a margin around the globe. While the skin 

 over the body of the fish is silvery white, a black streak extends 

 along the back and surrounds the eyes. The eyes are large and 

 striking from which it gets the name "Megalops." They are 



