USHING-LINES OF BEROE. 167 



square scales, disposed in a manner somewhat 

 similar to the boards of a water-wheel. Each of 

 these steps, "so to speak, is capable of motion 

 backward and forwards, and by their rapid and 

 successive motion a series of prisms are formed, 

 and bj them the light is decomposed to the pris- 

 matic colours; this iridescence is best seen when 

 the sun shines upon the creature. 



When the beroe has been watched for a little 

 time as it swims about in its glass prison, two 

 long and most delicate threads will be seen de- 

 pending from its exterior, and falling into graceful 

 curves as the creature ascends or descends in the 

 water. The threads are so exceedingly delicate 

 that they are not observed at a first glance; 

 and when they are seen, rather convey to the 

 spectator's mind the idea of spun glass, than of 

 any animated structure. Indeed, the whole crea- 

 ture looks as if it were formed of crystal, cut and 

 polished, and the threads almost seem to be spun 

 from its substance as it moves about. These 

 threads are called the fishing-lines, and if closely 

 watched are found to be fringed with smaller 

 tendril-like threads, that are dispersed along the 

 chief line, just as a fisherman attaches several 

 baits to his line by supplementary strings. The 

 fishing-lines can be entirely withdrawn into the 



