FRESH-WATER AQUARIUM. 59 



is a pretty plant for an Aquarium, and is, at the same 

 time, a curiosity, from having two sorts of leaves ; one set 

 being submerged and presenting thread-like divisions spread- 

 ing in all directions, another set float on the water and 

 have three lobes. There are several species of aquatic 

 crow-foots, and it is to this family (Ranunculacccc) that 

 the butter-cups, anemones, clematis, monkshood and lark- 

 spurs belong. Another species R. rurshii, or yellow wa- 

 ter crow-foot, is also common in this country. 



The plants I have mentioned are the most common and 

 best of the submerged class ; but the following may be 

 introduced, and arc, many of them, recommended by Dr. 

 Lankcster for that purpose. 



The Awl-wort (Suhdaria aquatica) which grows on the 

 margin of ponds. 



The SriKED Water-milfoil (Myriap/iyllum spicatum). This 

 is found very commonly in deep water. There are six 

 species of this genus. 



The Marestail (Ilippuris vulgaris) is not common in 

 the United States, but is sometimes found growing in ponds 

 and springs. 



The beautiful Villarsia (Villarsia nymjiJucoidcs) , which 

 is so highly recommended by English writers for the fresh- 

 water collection, is not found in this country. 



The Buckbean (Mcnyanthcs Irifoliata) grows in bogs. 



The Water-violet (Iloltonia injlata) is found in pools 

 and ditches pretty commonly. 



The. Water Speedwell ( Veronica palustris) is obtained 

 in this country, but not so commonly as, 



The American Brooklime ( V. Americana) while what 



