How to Dissect a Starfish

Dissection, although a controversial practice, teaches students about anatomy using a hands-on approach. In order to properly dissect a starfish, the student needs to become familiar with the tools of dissection and must know how to properly identify and label the starfish anatomy.

Instructions

1. Understand that the starfish is a marine animal that has a symmetrical endoskeleton. Starfish eat mollusks (mostly clams) and use hundreds of tiny tube feet for movement.

2. Know that the starfish has five legs called "rays" which are all connected at the central disk. Inspect the starfish, observing the spines on the rays and the tube feet which aid in locomotion. Locate the mouth which rests inside the central disk. Notice the ring of spines that surround the mouth. Label all outer features of the starfish before you dissect the starfish.

3. Prepare the tools you need to dissect the starfish. Necessary equipment includes a dissection tray, pins, a scalpel, scissors and a probe. Wear protective clothing and goggles to shield yourself from debris.

4. Pin the starfish to the dissection tray with the aboral (top) view facing you. Using your scalpel, cut off the tip of one ray. Make two long, parallel incisions (each incision close to the edge of the ray) from the tip to the central disk. Peel back the top layer of tissue and locate the lateral canal (where the tube feet attach) and the ring canal (where the lateral canals of all of the rays connect) and label these parts. The digestive glands are exposed; label these glands.

5. Cut tissue away from the central disk to find the stomach. Label the stomach and locate the gonads. It is impossible to detect the sex of the starfish without a telescope as the gonads of male and female starfish look identical.

6. Clean up your work area when finished with the starfish dissection. Ask your instructor to look at your labeled starfish to ensure you've found all of the parts required before you begin to clean up the area.

Tips & Warnings

• Follow all safety procedures while you dissect a starfish. Use the sharp instruments carefully and clean up your work station once the dissection is complete.