BENEATH TROPIC SEAS 



Not far from this part of the reef was a small 

 projection of the shallow shore zone, and I found 

 I could climb up the sides of a great globe of brain 

 coral until my face was on a level with this upper 

 floor — the attic of the reef, so to speak. One 

 defect of the open helmet is that it cannot be 

 tipped very far forward without flooding, so it is 

 impossible to assume my favorite jungle attitude 

 of observation — a worm's eye view. But here I 

 found I could lean comfortably outstretched with 

 my eyes on a level with the smaller coral, gorgonias, 

 and a scattering of Thalassia or tropical eel -grass. 



One of my first observations had to do with a 

 common triggerfish, Alutera^ of which I had taken 

 many specimens, but had no clue to the cause of 

 its shape and color. The solution came quickly as 

 I watched, for one of these triggerfish swam toward 

 me, and turned head downward when he reached a 

 small clump of eel-grass. 



He took hold of a bit of coral with his sucker 

 mouth and immediately set both vertical fins in 

 gentle, undulatory motion, the other fins, espe- 

 cially the long caudal, being furled, so that the 

 general body shape was tapering, which, together 

 with the mottled green color, transformed it into 

 a sea-weed frond or eel-grass blade. Now and then 

 the fish revolved on its base without letting go. 

 The trigger spine, slightly elevated, conveyed the 

 impression of a bit of shredded tissue. An addi- 

 tional aid in the deception was the considerable 

 variation of color in these fish, shifting from plain 



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