Science Art: Dissection of Asterias rubens, by Hans Hillewaert.

Starfish anatomy.

If you want to know the parts, according to Dutch Wikipedia, they are:

Legend
1 Arm
2 Ampullae
3 Radial canal
4 Gonads
5 Pyloric stomach
6 Rectal caeca
7 Pyloric caeca
8 Anus
9 Stone canal
10 Madreporite
11 Genital opening
12 Arm muscle

If you’re even more curious, a “madreporite” is a sort of water filter for starfish bodies, “ampullae” are little jug-shaped organs, and “caeca” is the plural of “caecum,” which is a kind of pouch, like the appendix in humans.