58 NEW SPECIE~ OF HYALINE DAPHNIA 
the- Brood Pouch, beneath the outer shell. There they 
remain until they are hatched, and the young are able 
to care for themselves. The eggs at first are round, with 
a central nucleus surrounded by oily globules. Gradually 
they elongate, and the young insect assumes shape, and 
gradually matures. Ultimately they may be seen moving 
independently in the pouch. A curved hook, arising from 
the back of the tail.piece, keeps them imprisoned. When 
the mother considers them old enough to fight life’s battle, 
she lowers the hook, and the young slip from their nursery 
into the water. When newly-born, the long shell-spine 
is bent round the abdomen, the tip being attached to the 
back of the head. This is freed in a few hours by its 
struggles, leaving a little ragged spot at the point of its 
attachment. The spine now looks so long that the body 
seems disproportioned to it. Gradually it assumes a more 
natural shape, and in two days is like the third form 
depicted. So far there is no sign of the peculiar elongation 
of the bead, so characteristic of this species. It approaches 
the shape of species found in Lake Henrietta, in America. 
At intervals of growth, the whole of the shell with the 
coverings and feathered sete of the feet are thrown off 
entire, and within seven days the peculiar form of the head 
appears. At first, it is not quite so pronounced, but grows 
more so at each successive moult. There is a good deal 
of variation in individuals in the depth of the cephalic 
cueve, and also in the length and curve of the shell-spine, 
In England, and on the Continent of Europe, about 
the month of October, they begin to lay a different kind 
of egg. These are called the winter or Ephippial eggs. 
A dark saddle-shaped organ begins to form on the back; 
it bears, usually, two very large elongated eggs. This 
saddle slips off at the next moult, and either floats, or 
sinks down into the niud. I have found these eggs floating 
among the decaying refuse on the surface of a pool. In 
cooler climates they remain during the winter, their cover- 
ing being sufficient to protect them from the frost, antil 
favourable conditions occur, when development begins, 
and the insects once more appear. It is somewhat peculiar 
that in the month of September, when I began to find them, 
many of the females bore their usual summer eggs, but 
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