66 Fresh Water Aquarium 



Small-fruited Nitella (Nitella microcarpa) 

 is a very graceful, but rather delicate aquatic. 

 The greatest of care should be taken in trans- 

 planting it from its native waters into the 

 aquarium, as the threadlike stems are very 

 brittle, sensitive to bright sunlight and 

 sudden changes of temperature. To insure 

 safe transportation, it should be carried in 

 water. It is especially interesting in being 

 one of the few plants which will show the 

 circulation of the sap under a fairly strong 

 magnifying glass. 



Swimming Arrow-wort (Sagittaria nutans) 

 is one of our native aquatic plants, and must 

 be counted under those of special merit. As 

 long as the plant is young, the leaves are 

 completely submerged, rather narrow and 

 ribbonlike, and therefore very much like 

 those of the Valisneria. Only a peculiar 

 curvature distinguishes them from those of 

 the latter plant. The long oval swimming 

 leaves seldom develop in the aquarium, and 

 only after a long growing period, when they 



