THE WONDERS OF AjAX REEF 309 



quite deeply and eventually grow too large ever to 

 escape, thus making themselves prisoners for life. 



Growing on the bottom in shallow places about 

 the reefs are beds of nulUpores, some of which have 

 quite the appearance of sea fans but their color is 

 green and their structure stony. The commonest 

 of these is Halimeda tridens, which is made up of 

 angular, jointed pieces. Some of the numerous 

 algae growing on or in the vicinity of the reef are 

 exquisitely beautiful in form and color. One of 

 these (Acetabularia) looks exactly like a delicate, 

 slender-stemmed but very green little mushroom. 

 The stem may be at most three inches long and its 

 little cap attain a diameter of slightly over half 

 an inch. A colony of them on the sea bottom is a 

 charming sight. Some of the algas are red, others 

 may be purple, brown, or intense bluish green. 

 There is a wealth and diversity of life on this reef 

 to keep one interested and filled with wonder for 

 months. 



But where are the moUusks or "shells," as they 

 are commonly called? In passing let me say that 

 it is no more proper to apply this term of "shells" 

 to the mollusks than it would be to use it for 

 lobsters or turtles. The shell of a mollusk is 



