THE MIcROSCOPE. 295 
the microscopic animals within the aquarium. The deposit is 
not entirely the evil it at first appears to be. 
When the collector is gathering aquatic plants for the aqua- 
rium and for the purpose of examining their stems and leaves 
for the microscopic animals they may be carrying, he should not 
lift them from the water, since that movement often dislodges 
the adherent creatures, washing them away beyond recovery. A 
better plan is either to scoop a mass of plants into the dipper, 
there selecting the parts desired, throwing out those discarded, 
and gently pouring the water and the acceptable portions into 
the waiting bottle; or the wide mouthed vessel may be partly 
submerged and the plants gently floated into it, The former 
plan is perhaps the better, since any animals that may be washed 
from their moorings will remain in the dipper and be trans- 
fered with the water to the collecting jar. 
No pond whose surface is mantled by a layer of Lemna should 
be passed without a sweep of the dipper. The little fronds and 
their delicate rootlets harbor many a curious creature. No slow 
stream where Myriophyllum abounds should be neglected.. Those 
feathery leaves are the favorite resorts of sedentary Infusoria, 
Rotifers and agile Entomostraca. The hornwort (Ceratophyllum) 
is likely to prove a valuable acquisition, but one that is usually 
less abundantly productive of microscopic supplies than Myri- 
ophyllum. Utricularia may also be examined with some prob- 
ability of success, although it is usually the most disappointing 
of all the water plants with divided leaves, probably because it 
has the habit of itself feeding upon any small animals that may 
venture too near that valvular entrance to its utricles. Anacharis 
Canadensis, “ water-weed,” as it is often called, is not usually a 
good hunting ground for sedentary Infusoria, neither is the 
lower surface of the water-lily leaves. Both are always sought 
by the microscopist when searching for certain other forms of 
microscopic life, worms for instance, but they are commonly dis- 
appointing when Infusoria are the objects sought. 
An old and water-soaked log, or a partly submerged and de- 
caying plank, are hailed by the microscopist with delight, since 
they always prove to be treasures when Infusoria are not desired. 
When they are wanted the old log and the rotting plank are of 
but little value. It is then usually a waste of time to scrape 
their surfaces. If you want aquatic worms these are the places 
