92 DIVERSIONS OF A NATURALIST 



surface by the alternate contraction and expansion of its 

 disk-like body, and then dropping gently through the 

 full length of the jar to the bottom, when it would 

 again mount. On the downward journey owing to its 

 transparency it would encounter unsuspecting, jerkily- 

 moving water-fleas, unwarned by any shadow cast by 

 the impending glass-like monster of half an inch in 

 breadth slowly approaching from above ; and as soon as 

 they touched it they were paralysed (by microscopic 

 poison-threads like those of the sea-anemones), and were 

 grasped and swallowed by the mobile transparent 

 proboscis (like that of an elephant, though certainly 

 smaller, and having the mouth opening at its end, 

 instead of a nostril), which hangs from the centre of the 

 disk-like jelly-fish. 1 



There are some glass-like transparent creatures, 

 including some small fishes, which live at 500 fathoms 

 depth and a good deal deeper on the sea bottom. We 

 know that the sun's light does not penetrate below 200 

 fathoms, so that one is led to ask What is the good of 

 being transparent if you live at the bottom of the sea, 

 at a greater depth than this ? There is also a very 

 beautiful prawn, which I dredged in Norway in 200 

 fathoms, which looks like a solid piece of clearest, 

 colourless glass. And then there are some very beauti- 

 ful little stalked creatures (called Clavellina), fixed to 

 the under-side of rocks in the tidal zone, which are 

 absolutely like drops of solid glass an inch long. One 

 cannot easily imagine how colourless transparency can 

 be of " life-saving value " to these varied inhabitants of 

 the dark places of the sea bottom any more than we 



1 See " Science from an Easy Chair " (First Series, 1910), p. 60, for 

 a further account and figure of the freshwater jelly-fish. 



