THE EIGHT-RAVED POLYPS 



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Very slight irritation, such as is produced by tapping on the glass of the aquarium, 

 is enough to call forth flashes. If the animal is taken in the hand, either in or 

 out of water, still brighter luminous spots and streaks are seen. Repeated careful 



A SEA FAN (Gorgonia verrucosa), WITH A SHARK'S EGG FIXED To ITS BRANCHES. 



(Natural size.) 



experiments have revealed the fact that the streams of light follow regular courses. 

 There are two kinds of streams; the one connected with the polyps proper, and 

 visible on the dorsal side of the feathers, and the other connected with the zooids, 

 and appearing on the lower side. The two streams appear at the same time, as a 

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