THE WONDERS OF AJAX REEF 315 



that lives on the sea fans. The lips of its shell 

 are rolled and folded in and it has a rather sharply 

 defined ridge around its center. The base and a 

 streak on the back are whitish while the sides are a 

 warm fawn color. It so closely harmonizes with 

 its host that, no doubt, it fools its enemies very 

 successfully. Another related form (Amphiperas 

 acicularis) is more slender and delicate; when it 

 grows on a yellow sea fan it is also yellow, when 

 on purple ones it is purple. 



Among the Florida reefs life reaches its high 

 tide of strenuous existence; it attains to its zenith, 

 its noonday, its full glory. Nowhere is compe- 

 tition for food and existence more fierce than 

 among these low rocks and in these coral sands. 

 As a natural consequence here are to be seen and 

 studied the most varied and remarkable devices 

 for protection. 



During a visit to Sand Key reef we all descended 

 by turns under a diving helmet which Mr. Hen- 

 derson had on board. This device consists of a 

 brass hood which encloses the head while resting 

 on the shoulders, so weighted and adjusted that 

 the wearer can walk with ease on the bottom or 

 study and collect his specimens while air is being 



