THE OPEN SEA 73 
Foraminifers float in the surface-waters, and 
this is true of most of the very beautiful 
Radiolarians, which have usually shells of 
flint, and have established an internal partner- 
ship with microscopic Alge. Perhaps it is 
this partnership that has made them so suc- 
cessful, for there are 5000 different kinds, and 
the number of individuals is past all telling. 
The Stinging Animals are represented by 
swimming-bells, most of which are budded 
off from shallow-water zoophytes; by true 
jelly-fishes or Medusz, rhythmically contract- 
ing and expanding their translucent discs; by 
strange colonies like the Portuguese-Man-of- 
War; and by the delicate Ctenophores. One 
of these called Venus’s girdle, like a ribbon of 
flexible glass, iridescent and phosphorescent, 
is one of the most beautiful animals of the sea. 
There are not a few open-sea worms, some 
of them, like the Arrow-worm, quite trans- 
parent; and there are actually a few sea- 
cucumbers which have departed widely from 
the sluggish habit of their shallow-water and 
deep-water relatives. 
Jointed-footed Animals are represented by 
many kinds of Crustaceans, from gorgeous 
prawns to pinhead-like “water-fleas”; and 
