278 Dwellers of the Sea and Shore 



that had lured me to the sea. Such are the Illusions 

 of the young! Here am I, not engaged In romancing 

 about the ships and men that sail the surface of the sea, 

 but In detailing the lives of the lower creatures that 

 range Its depths. 



The nightly phosphorescence of the sea — which was 

 the phenomenon just described — is as familiar to the 

 traveler In the tropics as are the flying fish in the day. 

 Yet not everybody knows that this Is caused by the 

 presence of billions upon billions of little animals each 

 so minute as often to be scarcely visible to the naked 

 eye. There are a number of forms which may produce 

 this amazing spectacle, but the largest here Is much 

 smaller than the head of a pin. This one Is Noctiluca, 

 the most numerous and most widely distributed of all 

 the light-producing creatures of the sea. In general. Its 

 shape may be likened to that of an apple whose stem Is 

 drawn out Into a w^hlplike lash. It Is with the aid of Its 

 large lash, or flagellum, that the tiny animal drives 

 Itself through the water. In structure, It Is transparent 

 and jellylike, and the entire organism consists of but a 

 single cell. Now, this animal, small as it is, lives upon 

 other organisms still smaller; and under a powerful 

 glass, it may be observed to take In Its food, selecting 

 such things as are suitable in the surrounding medium, 

 showing that it has Its likes and dislikes the same as 

 higher creatures whose bodies are composed of millions 

 of cells. Its mouth Is situated at the base of the flagel- 

 lum, and Is a groovelike orifice extending nearly half- 

 way around one side. From the mouth Issues a small 

 hair-like organ, a second flagellum. The little spherical 

 unit, like all cells, is made up of three principal parts: 



