TWO-LAYERED ANIMALS— PHYLUM COELENTERATA 129 



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Photo by W. K. Fisher 



Fig. 9.8. Jellyfish. Pelagia that have been left on the beach by the receding tide. 



the skin. Not all of the large jellyfish sting man — the white jellyfish 

 (Aurelia) can be handled without ill effects, but you must be careful of 

 the red jellyfish. 



Class — Anthozoa 



The word Anthozoa means flower animals and, when genera of this 

 class are seen grouped together in warm tropical waters, this name cer- 

 tainly seems appropriate. The beautiful display of color harmony and 

 body form rivals the most gorgeous flower garden that has ever been 

 grown on land. One member of this class, the sea anemone, is named 

 after a flower, the anemone; but, seen in its natural habitat, it seems to 

 resemble more closely a chrysanthemum, a marigold, or a dahlia in its 

 different forms and colors. This animal is the polyp type in shape, like 

 hydra, but it is much larger than the other polyps we have studied and 

 has more tentacles which come out around the mouth and appear like the 

 petals of a flower. While, as we have indicated, they are very abundant 

 in tropical waters, they are by no means restricted to these areas. They 

 are common, for instance, along our north Atlantic coast where they 

 attach themselves to piers and other solid objects near the shore. The 

 genus usually studied in the laboratory, Metridium, is such a form and, 

 after a glance at this dull brownish animal, the student may decide that 

 all of the descriptions of the beautifully colored sea anemones were exag- 

 gerations, to say the least. However, it is a general rule that animals 

 living in tropical waters are brilliantly colored, whereas those living in more 

 temperate and frigid waters are dull in their coloration; and the sea 

 anemone is a good illustration of this point. The dull coloration is a 



