ACALEPILE. GENERAL SUMMARY. 479 



disappearing with great rapidity when alarmed by the roughness 

 of the waves. 



1039. Our account of the Acalephze cannot be better 

 summed up than in the words of M. Peron : " Among the 

 animals of this family," he observes, u we find the most import- 

 ant functions of life performed in bodies which offer to the eye 

 little more than a mass of jelly. They grow frequently to a 

 large size, so as to measure several feet in diameter ; and yet we 

 cannot always determine what are their organs of nutrition. They 

 move with rapidity, and continue their motions for a long time ; 

 and yet we cannot always satisfactorily demonstrate their mus- 

 cular system. Their secretions are frequently very abundant, 

 and yet the secreting organs remain to be discovered. They 

 seem to be too weak to seize any vigorous animal, and yet fishes 

 are sometimes their prey. Their delicate stomachs appear to 

 be wholly incapable of acting upon such food ; and yet it is 

 digested within a very short time. Most of them shine at night 

 with great brilliancy, and yet we know little or nothing of the 

 nature of the agent which produces so remarkable an effect, or 

 of the organs by which it is elaborated . And, lastly, many of 

 them sting the hand which touches them ; but how, or by what 

 means, they do so, remains a mystery/' 



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