MABINB TANK. 105 



in abundance covering the stones on every sandy beach 

 near our city. The fronds of this species are variable in 

 width from a fine green ribbon, hardly wider than sew- 

 ing thread, to sometimes, such a width as to cause it 

 to be mistaken for the last species described. When it 

 decays, it becomes pearly white, and in this state chil- 

 dren call it sect-thread. If we seize a large bunch of this 

 plant, and, taking it home, put it into fresh salt-water 

 in a glass jar, we shall most likely find we have got 

 more than wo expected, for its numerous fronds are the 

 haunts of many of the smaller animals, such as shrimps, 

 sandskippers, and worms, together with, sometimes, mol- 

 luscs, and such small fish as minnows, and the like. It 

 grows very well in the Aquarium, and aerates the water 

 capitally. It looks well when about a quarter to a half 

 of a tank is planted with it, so as to make a bottom 

 of a grassy appearance, and forming a miniature forest, 

 where, 



" Under the shade of melancholy boughs," 



fish and smaller inhabitants take refuge. 



Enteromorpha vdcslinalis resembles very much the last 

 species, but is wider in proportion to its length ; and its 

 frond is also tubular and hollow. This is one of those 

 curious salt-water plants that will live sometimes in brack- 

 ish water, and even has been observed in fresh-water 

 streams. It varies in length and breadth, sometimes short 

 and narrow, at other times two feet broad and three 

 inches in length. This species, unlike the last, is never 

 hranched ; but the fronds grow singly and alone. It looks 



