16 THE BUTTERFLY VIVARIUM. 



The back, as it will have been seen, will be like 

 the front, with the exception that the frame will be 

 solid — that is, of zinc or slate — up to the same height 

 as the water-line in front. A variety of effect 

 might, indeed, be obtained, if desired, by making 

 the solid lower portion of the frame ascend gradually 

 from the water-level, at the front angles, to some 

 four or five inches higher at the back, so as to make 

 the land rise all round from the level of the water, 

 like the seats of an amphitheatre, till it reached the 

 top of the solid portions of the frame at the sides 

 and back ; taking care not to follow the line too 

 arbitrarily, but, for the sake of the picturesque, 

 varying it by a few irregular pieces of moss-covered 

 stone, etc. ; and this kind of picturesque undulation 

 should also be observed, as far as convenient, in the 

 general level of the soil. 



Before filling the water portion of the Vivarium, 

 the bed of the little lake should be varied by a few 

 groups of tasteful rock- work, which, at one or two 

 points, might be made to conceal small shallow 

 flower-pots, containing garden mould, in which 

 water plants requiring earth may be planted, such 

 as Valisneria spiralis, or a small plant of Calla 

 Ethiopica. The other portions of the bed of the 

 tank may be covered with small, and, if possible, 



