656 THE POPULAR SCIENCE MONTHLY. 



duction are curious. In some a portion of the body of the parent 

 begins to grow out, and this continues until a perfect bud-like 

 protuberance is the result, and then the bud drops off and, after 

 various interesting changes, becomes a fully formed jelly-fish. 

 Sometimes the parent begins to divide, and actually splits into 

 two parts, each of which becomes a perfect animal. 



So great is the transparency of most jelly-fishes that they are 

 scarcely visible ; but at night, what a change takes place ! When 

 a school is passed, the water becomes suddenly transformed to a 

 mass of liquid fire, composed of individual balls that together, on 

 account of their great number, appear as one vast sheet of light. 

 When they are disturbed, their brilliancy is increased. Far differ- 

 ent from the jelly-fish in structure, but resembling it in its phos- 

 phorescence, is Pyrosoma, a colony of animals often found in 

 these warm waters, which together form a fleshy mass, possess- 

 ing no remarkable points by day, but at night becoming most 

 brilliantly phosphorescent. In the mass, six inches in length, 

 there are hundreds of separate animals, each like the others, all 

 massed together in a common colony. They are very curious, 

 for, while most of the young remain to help build the mother 

 colony, some become entirely separate, and, after swimming about 

 for a while, begin a new cluster that soon takes the form of the 

 parent group. Each group has a regular shape just like the 

 original one. The same is true of corals and most other clusters 

 formed of more than one individual. 



In our surface towings we find many beautiful animals, but 

 none have impressed me so strongly as the so-called sea-butterflies. 

 They are small, usually, and seldom found in abundance, and, 

 being thus inconspicuous, are not likely to be seen by those not 

 specially searching for them. Every color is found in these beau- 

 tiful forms, and, as they float upon the surface, with their wing- 

 like expansions spread out to catch the wind, but a small amount 

 of imagination is needed to transform them into true butterflies 

 accidentally fallen into the water. They have a very light and 

 beautiful shell, with an air-chamber above to serve as a float, 

 while from a lower compartment the wings are expanded. When 

 startled, their sails are withdrawn into this chamber, and the 

 oddly shaped shell is alone exposed to view. Sea-butterflies can, 

 by arranging their sails so as to utilize the wind in the most 

 effective manner, guide their course to a certain extent, just as 

 the ship can proceed against a head wind. Their shells, which 

 are often taken without the animal, present many very peculiar 

 forms, from the nearly round to the long, sharply pointed ones, 

 some with spines, others perfectly smooth ; and we can see them 

 in every conceivable color, the glassy, transparent kinds, the 

 milk-white, and masses of the most brilliant colors, so confusing 



