Biologic evolution

Standing position of corbicula in the imagined bottom of the water.

The part in the apex of shell of corbicula's shell peels off the skin of the shell and
has whitened.


Why
Does the part in the apex of shell whiten?
It was thought that the husk top part corresponded directly to sand in the bottom of
the water, it rubbed against each other to sand, and the skin of the shell peeled off.


When you do the apex of shell below
There was a water pipe on the side with the ligament, and the water pipe was made to
become the near the surface of the water.
When it is a position of this shell, the part with which brown is dirty becomes shape
that sticks to the surface of in sand or sand.
When seeing from side
This shape is a standing of the shell that explains easily most.
It to be easy put together it on the flow of the river, the shape of corbicula's shell
is imagined to be a triangle.


The triangle is a triangle that is sharper than other shellfishes' shape.
It is imagined that the purpose of it is to secure the best standing position by using
the flow of the river.