H YD ROWS AND JELLY-FISHES. 



After this separation has taken place, the tentacies 

 begin to grow ; and when the animal is complete, it 



is bordered all around the margin 

 by the fringe which they form. You 

 see that in order to have the bulging 

 side above, as it is in the picture 

 (32), each one, as it floated off, 

 must have tumed upside down ; for 

 if they retained the position which 

 they have while still attached to- 

 gether, their shape would be like 

 that of a saucer standing on its bottom, as it is usually 

 placed. But each one, as it leaves the pile, turns a 

 somerset ; and though it has still the shape of a saucer, 

 it is of a saucer overturned and resting on its edge, the 

 edge being scalloped ; for the fringe of tentacles around 

 the margin is not then fully formed. 



No 31- 



No. 32. 



There are a variety of these singular, self-dividing 

 Hydroids and of the Jelly-Fishes produced by them, 

 all of which grow to a considerable size. The most 

 common is the so-called white sun-fish (No. 32),* 

 seen in our bays and along our wharves. It is remark- 



* No. 32 : Aurelia 



