SQUIRTS, POLYPS, AND JELLY-FISHES. 65 



the sun, and in a ehoi't time it will have almost com- 

 pletely disappeared through evaporation. "Whence 

 came these singular creatures, and whither do they 

 go ? The greater number of them begin life in a 

 quiet way as minute buds on the stems of the cam- 

 panularians and their allies. After expanding and 

 acquiring definite shape they drop off from the 

 parent, and pass into that stage which fits them for 

 a free existence on the oceanic surface. The me- 

 dusa thus formed for some time leads the life of 

 an independent rover, but after a certain period it 

 gives birth from eggs to elongate tiny bodies, known 

 as planulse, which soon attach themselves and grow 

 up into the grandparental form of the hydroid 

 colony. Thus a complete cycle of changes is 

 brought about. Some of the medusae give birth 

 directly to other medusae, without passing through 

 any of the intermediate conditions that have just 

 been noted. 



The transition from the delicate sea-bubbles, 

 whose existence, it would seem, could be wiped 

 out by a mere blow of the breath, to the large un- 

 sightly jelly-pads that lie scattered over the shore 

 after high-water, is an abrupt one, but yet the two 

 objects are much the same thing. One is merely a 

 large jelly-fish, while the other is a small one. But 

 on the open sea even the large Cyanea, whose disk 

 or bell measures two yards in diameter, and whose 

 wilderness of tentacles floats out to a distance of 

 a hundred feet or more, is a beautiful object, re- 

 flecting its brilliant tints of pink, yellow, blue, and 

 brown to striking advantage. When cast on the 

 e 6* 



