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. 



