e we are again reminded of
Saturn and its rings, which seems to have its counterpart here. These
rings disappear, and now once more out of the yolk mass loom up little
dots as minute as before; but they are round instead of angular, and
those nearest the Purkinjean vesicle are smaller and clearer, containing
less of oil than the larger and darker ones on the opposite side. From
this time the yolk begins to take its color, the oily cells assuming a
yellow tint, while the albuminous cells near the vesicle become whiter.

Up to this period the processes in the different cells seem to have been
controlled by the different character of the substance of each; but now
it would seem that the changes become more independent of physical or
material influences, for each kind of cell undergoes the same process.
They all assume the ordinary cell character, with outer and inner
sac,--the inner sac forming on the side, like the Purkinjean vesicle
itself; but it does not retain this position, for, as soon as its wall
is formed and it becomes a distinct body, it floats away from the side
and takes its place in the centre. Next there arise within it a number
of little bodies crystalline in form, and which actually are wax or oil
crystals. They increase with great rapidity, the inner sac or mesoblast
becoming sometimes so crowded with them, that its shape is affected by
the protrusion of their angles. This process goes on till all the cells
are so filled by the mesoblast, with its myriad brood of cells, that
the outer sac or ectoblast becomes a mere halo around it. Then every
mesoblast contracts; the contraction deepens, till it is divided across
in both directions, separating thus into four parts, then into eight,
then into sixteen, and so on, till every cell is crowded with hundreds
of minute mesoblasts, each containing the indication of a central dot or
entoblast. At this period every yolk cell is itself like a whole yolk;
for each cell is as full of lesser cells as the yolk-bag itself.

When the mesoblast has become thus infinitely subdivided into hundreds
of minute spheres, the ectoblast bursts, and the new generations of
cells thus set free collect in that part of the egg where the embryonic
disk is to arise. This process of segmentation continues to go on
downward till the whole yolk is taken in. These myriad cells are in
fact the component parts of the little Turtle that is to be. They will
undergo certain modifications, to become