54 THE AQUARIAN NATURALIST. 



clear jelly, and exhibit no traces of their elegant form 

 and ornamental appendages. 



Even when in the jar or basin, they are often, on 

 account of their extreme transparency, very difficult 

 to distinguish ; but by placing them in the sunshine, 

 or beside a strong artificial light, we see their shadows 

 floating over the sides and bottom of the vessel, like 

 the flitting clouds on a landscape. These soon guide 

 us to the creatures themselves, and before long we 

 distinguish their brilliant ocelli, and other coloured 

 portions of their structure. 



The next step is to secure such of the smaller spe- 

 cies as we wish to examine closely, and transfer them 

 to the watch-glasses or small phials. To do this is 

 often not an easy task, for when alarmed they are 

 exceedingly agile and alert ; so that if we attempt to 

 capture them with a tea-spoon, they usually escape, or 

 if taken, owing to their slippery nature, slide out. 

 This difficulty may be got over by using a small but 

 deep glass spoon, with its handle set very obliquely, 

 from which they are easily transferred to a watch- 

 glass, and thus submitted to microscopic examination. 



The Medusae were known to the Greeks and Romans 

 by the names of Trvev/jua Od\dcrcriov and Pulmo mari- 

 nuSj which we may translate by Sea -lungs, on account 

 of the constant rhythmical action of their gelatinous 

 disc, which, alternately expanding and contracting, 

 reminds the spectator of the heaving and subsidence 

 of the bosom during respiration. 



The movements of the Medusae are slow, indicating 

 that these creatures possess a very feeble amount of 

 muscular energy ; nevertheless they must be incessant, 



