CCELENTERATA 



sting cells. Indeed, a few forms, for example, among the Cubomedusse, 

 Fig. 9, may produce quite serious results. 



Anthozoa. This is the most important of the ccelenterate classes. 

 Two species were formerly, probably still are, eaten in Italy under 



FIG. 10. A sea-anemone, Metridium marginatum, partly cut away so as 

 to show its structure. Xi. i, intermediate zone; 2, lip; 3, siphonoglyph; 4, 

 gullet; 5, inner edge of gullet; 6, edge of mesentery; 7, cavity of tentacle; 8, inner 

 ostium; 9, outer ostium; 10, primary mesentery; n, muscle band on primary 

 mesentery; 12, abnormal tertiary mesentery; 13, secondary mesentery; 14, tertiary 

 mesentery; 15, quaternary mesentery; 16, reproductive gland; 17, mesenterial 

 filament; 18, opening for mesenterial filament. (From Hegner, College Zoology, 

 redrawn from Linville and Kelly.) 



the name "Ogliole." The corals are the most important of the cce- 

 lenterates. They have practically the structure of the sea anemones 

 but secrete at their attachment a limestone base that forms the well- 

 known coral reefs, so dangerous to shipping in many parts of the tropics. 

 2 



