148 THE SEA-SIDE AND AQUARIUM. 



light than usual. On looking at the Aquarium, I 

 found that the Ulva had risen in the water, and was 

 hanging in most elegant festoons from the surface, 

 forming emerald caves and grottoes, such as a sea- 

 nymph would love. Even at a little distance it was 

 a pretty sight, but a closer inspection revealed still 

 more beauties; for, being excited by the unwonted 

 light, the plant had poured forth so much oxygen, 

 that its entire surface was thickly studded with tiny 

 sparkling beads, that had buoyed up the whole plant, 

 each bubble acting as a miniature balloon. When, 

 however, a black cloud came over the sun, the bubbles 

 soon detached themselves, ascended to the surface, 

 and as there was no more to take their place, down 

 dropped the plant to the bottom." 



Totally opposite in character to the Ulva above men- 

 tioned is the Enteromorpha compressa, or Sea-grass, 

 which is also extremely useful, especially in forming a 

 kind of close thicket at the bottom of the tank. In 

 it the fishes are very fond of wandering, either for en- 

 joyment or protection from the glaring heat of the sun. 

 This sea-plant grows in great abundance upon rocks. 

 Their surface is, in many places, completely covered 

 with its verdure. I would advise the reader not to 

 omit, when at the sea-shore, plucking a few handfuls 

 of this weed to drop into his Aquarium. By this 

 means a splendid treat is insured to the captives of 

 the tank. No sooner is it dropped down than num- 

 bers of hungry mouths begin snap-snap-snapping, at, 

 a stranger would think, nothing at all. But if a 



