74 Dwellers of the Sea and Shore 



the comb jellies ar^ far more conspicuous than the 

 others. 



The comb jellies, or Ctenophora, exist In every 

 ocean. They are nearly as abundant in the arctic as in 

 the temperate and the tropical waters. Of the several 

 hundred different species which make up this group, 

 perhaps less than a half dozen are known to other per- 

 sons than professed naturalists. Even these few 

 would doubtless have escaped common observation 

 were it not for the extraordinary play of prismatic 

 colors that is reflected horn their bodies in the sun- 

 light; for otherwise, because of their great transpar- 

 ency, they are practically invisible. 



One particularly common comb jelly is the exquisitely 

 beautiful "rainbow jelly" (Mnemiopsis leidyi) which 

 makes its appearance on our Eastern coast during the 

 hottest season of the year. In general form it is pear- 

 shaped, somewhat flattened on two sides. Specimens 

 six inches in length are not uncommon, but the great 

 majority are more nearly four inches. Whenever one 

 of these delicate creatures is encountered, others are 

 almost certain to be in the immediate vicinity; they are 

 gregarious — that is, they collect together and wander 

 about by thousands. Although not a rapid swimmer 

 it is a graceful one. It progresses with an undulating 

 motion by means of eight rows of flat hairlike processes, 

 or cilia, arranged in meridianal lines over the surface. 

 The filmy gelatinous character of its body substance 

 makes it extremely difficult to handle, and it cannot be 

 lifted from the water without injury; yet, in spite of its 

 delicate structure, it captures small fishes and crus- 

 taceans for its food, and has been known to devour 



