Biologic evolution

When you examine the mussel by the Internet

It is the same as mussel to live in the Mediterranean sea.

Did you come to Japan in the navigation of the ship?

It is mussel's hinge.

A brown arrow is a skin with which the shell is covered.

The hinge is shape quite different from hunting and the ark shell.

There is no hinge, and the skin puts it between a right, left shells.

It is very easy shape.

Mussel's shape and action different are interesting with the shellfish in Japan.

What evolved from the mussel is imagined.

When mussel's Tait evolves outside the shell, the prawn.

When mussel's Tait evolves in the shell, fishes.

The starting point of fish's evolution is being written in "Field animal" with
the spine inside the body and the reference book.

The shellfish but I have imagined it before making the spine.

Am my imagination this, and please do not take it amiss.