RIVER GARDENS; 
which they cover the surface of still waters. In the 
Vivarium the Duckweeds are found of great advan¬ 
tage, from their peculiar habit of growth, which 
affords a natural screen to the animals below, when 
the sun is too powerful; and Dr Lankester tells 
us, in his instructive little work, that these plants 
harbour a number of minute creatures, among 
which the microscopist may hunt for some of his 
most valued game, which at the same time pro¬ 
vides food for the fish and other inmates of the 
Aquarium. All that is necessary to establish a 
Duckweed screen is to remove a small portion of it 
from the surface of some neighbouring pond, when it 
requires no other replanting than merely throwing it 
into the Aquarium, where, being strictly a floating 
plant, it soon establishes itself and spreads rapidly. 
The loose pieces should, however, he picked out, as it 
is only in a mass that it produces a pleasing effect. 
The Cape Aponogeton is one of the most desir¬ 
able plants for the Aquarium, as it continues flower¬ 
ing nearly all the year round, and the flowers 
themselves, besides being very pretty, are sweet- 
scented. It is quite hardy, and grows with great 
luxuriance in our open ponds. In the Botanic 
Garden, in Edinburgh, and the tanks of the Zoolo¬ 
gical Society, in Regent’s Park, London, this plant 
38 
