108 



MADKEPOKES. 



discover a special provision : for the stem, instead of 

 being hard, resembles horn, and is more or less 

 flexible ; or is composed of flexible horny matter, 

 with calcareous knots, placed at regular intervals. 

 How obvious here is all-wise design ! 



ISIS HIPPURIS. 



In which may be observed the living gelatine with its polyps, and the 

 intermixture of horuy and calcareous matter in the stem, 



If the branching stems of a madrepore be exa- 

 mined, the unassisted eye may observe multitudes of 

 minute cavities on its surface. But let the micro- 

 scope be employed, and each of these cavities proves 

 to be a beautifully constructed cell, remarkable for 

 the exquisite precision of its form, as the engraving 

 will demonstrate. 



