218 



TOILERS IN THE SEA. 



struction of coral rock (fig. 42). Let those who please 

 quibble over the terms of definition, and call it work 

 or play, as suits them best; the animals are, neverthe- 

 less, the constructors of the coral rock. It is not so 



FIG. 42. MADREPORES AND CORALS. 



readily that we can select a type of a definite char- 

 acter, and, having briefly sketched its life history, 

 point to it as the coral animal, as could be done with 

 some other groups, since in this case there is more 

 than one type of coral animal, and the details which 

 would answer for one could not be applied to all. 

 Hence it will be necessary to indicate, separately, the 



