60 



THE FxVMILY AQUAlilUM. 



Potamogeton densus — (Pond-weed.) 



with waved leaves attached to the stem opposite each 

 other. The P. Crispus has a reddish stalk with brownish^ 

 green leaves, and adapts itself to any vessel. The only 

 objection that may be urged to the best of these Pond- 

 Weeds is the relish for them manifested by the Molluscs 

 which an Aquarium demands (as will be seen by and by), to 

 keep it in wholesome order. The little creatures will 

 leave all other plants to feed on these, and thus soon de- 

 stroy their beautiful appearance. 



