COASTLINES 



their structures than the Siphonophores, are still baffling 

 scientific explanation, while of the origins and habits of 

 some of them scientists know little or nothing. 



New and hitherto unknown species of jelly-fish may 

 appear suddenly along a particular section of coastline. 

 The animals may simply swarm in the sea and be 

 washed ashore in great numbers. Then, with similar 

 suddenness, they will vanish as mysteriously as they 

 appeared. Whence they come and whither they go no 

 one knows. Sometimes they will reappear after a lapse of 

 many years ; sometimes a completely new species will come 

 out of the sea, disappear into it again, and be seen no 

 more. 



Nor are they always tiny creatures which may have 

 been overlooked on past occasions : some of the creatures 

 performing the appearing-disappearing act may be 

 several feet in diameter. But whether they are produced 

 by monstrous hydroidal forms completely unknown to 

 us, moving in the depths of the sea, or are the offspring 

 of other free-swimming Medusae in the surface waters, 

 no one knows. 



To many people the word "jelly-fish" conjures up a 

 picture of a sea creature of fairly simple construction : 

 the average person has seen a few forms at the seaside 

 or in aquaria and has no conception of their stupen- 

 dous variety and vast differences in structure. Fortu- 

 nately, the jelly-fish most frequently found along British 

 shores are quite harmless. It is not unusual in summer to 

 see numbers of them stranded on flat sandy beaches, by 

 the combined action of tide and onshore wind. Or you 

 may go for a row on a warm and sunny day and glimpse 

 many of the Amelia (the jelly-fish most common to our 

 coasts) drifting lazily just below the surface. Those 

 stranded on the beach may appear flabby, nasty-looking 

 objects : those seen over the side of the boat look very 

 different — colourful, graceful, like flowers of the sea. But 

 in neither case do the jelly-fish seem extraordinary. 



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