Fisrt the description, then the mystery.
Inside the clear egg shell, after all the divisions, on the second day they appear to hatch or metamorphos. At this time they suddenly GAIN a clear snail like shell around the abdomen, yolk and body parts. The head or two coiled sensory organs extends from the shell opening. Their eyes are right at the edge of the shell and mostly not visible in the pictures. The small foot is snail like under the shell. They can move fairly rapidly as they explore the outer walls of their confining egg case and twil around in the sphere. Its hard to focus because the egg case is clear, the protective shell is clear and the animal is white translucent. In the enlarged picture, the one most toward the middle you can see the foot to the right, the sensory organs coiled to about 1 o'clock and the shell to the left side. Inside the middle of the shell is the animal and that little dense spot inside the shell is some yolk material. Since they are flipping all around in their weightless spheres, you can see them from all kinds of angles.

The Mystery:There is an inner snail like shell that is the developmental home now and protects these larva in their first hours after hatching. It appears in that one majic moment on the second day after the "stem" cells have divided numerous times. Where does that "instant shell" come from???

Magnified x60:


Magnified x200: