being again shed after the young have been 
brought to maturity. 
Second, at certain times daphnias may be 
seen with a dark opaque substance inside the 
rear part of the shell, which from _ its 
resemblance to a saddle is called the ephip- 
pium. This contains two oval bodies, each 
consisting of an ovum covered with a very 
tough casing enveloped in a capsule which 
The first traces 
of the ephippium are seen after the third 
opens like a bivalve shell. 
molt as green matter in the ovaries, which 
differs both in color and appearance from 
the eggs. After the fourth molt this green 
matter passes from the ovaries into the 
open space under the shell on the animal’s 
back and there develops into the ephip- 
At the fifth molt this is thrown off 
and the ephippium, with the two eggs en- 
pium. 
closed, floats on the water or sinks into the 
mud until the next spring, when the young 
are hatched. This provision of 
nature is destined to afford protection to 
the eggs, which are to endure the winter’s 
cold. The cast shell of daphnia carries 
with it not only the covering of the limbs, 
but of the most delicate hairs and setae 
which are attached to them. 
The young, recently hatched daphnia 
curious 
differs greatly in appearance from the ma- 
ture animal. It is an odd-looking, sprawl- 
ing thing, moving by quick jerks, having no 
bivalve shell, and only three pairs of limbs. 
This is the food upon which very young gold- 
fish thrive and grow so rapidly. The mature 
daphnia are too large to be swallowed. 
Young goldfish have been observed to 
follow female daphnia about in order to 
feed upon the young as they are extruded. 
The food of daphnia consists of small 
particles of decaying animal and vegetable 
matter and such living animalcules as they 
can capture and devour. Daphnias are 
small creatures, and any creatures which 
they can capture and eat must be very 
indeed. Yet the largest part of 
daphnia food, in the natural environment, 
consists of just such creatures. 
small 
25 
But, if daphnias eat small creatures which 
cannot be seen with the naked eye, how 
are we to catch, much less propagate, them 
to feed to daphnias? 
simple. 
The answer is very 
These small creatures are called 
Infusoria, because they invariably make 
their appearance in infusions, especially in- 
fusions of hay. They consist of an indis- 
criminate assemblage of minute, mostly 
microscopic, animal and vegetable organ- 
Some of the more common ones are 
called Stentor, Chilodon, Paramaecium, 
Stylonchia, Vorticella, Chaetonotus, etc., 
all 
daphnia. 
isms. 
of which are greedily devoured by 
To keep daphnias alive and have them 
increase successfully, the following should 
be observed : 
Do not crowd them, on the same prin- 
ciple that successful breeders of fish do not 
crowd an aquarium with fish. Daphnias, 
while often found in stagnant water, re- 
quire oxygen to live; therefore, unless 
growing plants are present, well aerated 
water should frequently be added. 
The best plan is to keep the daphnias in 
a receptacle in which water plants are grow- 
ing and add the water containing the infu- 
This 
a re- 
soria from time to time as needed. 
water is prepared as follows: Place 
ceptacle containing a quantity of hay and, 
if possible, some fresh water algae such as 
Spirogyra, Zygnema, Vaucheria, Oedogo- 
nium, ete., in a warm, dark or shaded place 
After this all 
that is needed is to stir the water slightly 
for ten days or two weeks. 
and dip out a quantity, which is poured 
into the water containing the daphnias. 
By the foregoing means the author has 
raised countless numbers of daphnias from 
a few hundred original ones, and can do so 
in winter as well as in summer. 
The Possibilities of the 
Home Aquarium 
Tracy H. Hotmes 
Chicago 
An aquarium with water clear as crystal 
and capable of sustaining fish life for an 
