1 88 



ZOOLOGY 



medusoids are the only known exceptions. Cordylophora, a 

 colonial polyp, is found in brackish tidal waters, and has been 

 discovered in inland rivers. It seems to be a species in process 

 of adjustment to fresh-water conditions. 



Fig. 86. 



Fig. 86. Physalia, the Portuguese Man-of-Wap. After Agassiz. 



Questions on the figure. — For what is this animal remarkable? To what 

 group of codenterates does it belong? Compare Hujdey's figure of the same 

 animal (see Parker and Haswell's Zoology, Vol. I, p. 163, and other reference 

 texts). What various types of polyps are represented in the colony? Compare 

 with Fig. 87. 



The jelly-fish are used as food by fishes and whales, though 

 they cannot contain much solid matter. The group has little 

 economic value. The red coral of the Mediterranean, of very 

 slow growth, is used in making jewelry. The reef -forming corals 



