1. Label external anatomy. Procedure for Squid Dissection 1. Label external anatomy. Place the squid with the dorsal (back) side up in the dissecting pan (fin side up). Use the hand lens to examine the suckers on the tentacles and arms. Pop out one of the supporting rings in a sucker using your fingers. Spots or chromatophores on the skin are cells containing pigment surrounded by a muscle that can make them swell in size. The squid can change colour rapidly to camouflage themselves, attract mates, and to communicate with each other.

1. (b) Label the funnel Turn the body over, ventral side up, and locate the funnel (a deflated fleshy tube located at the base of the head). A squid swims by squirting water from the mantle through the funnel. The direction it swims depends on which way the funnel is aimed. Move the funnel and note its flexibility.

Manipulate them (open and close) as if the squid were eating. 2. Remove beak and radula Open and close the beak. Pull out the beak. Manipulate them (open and close) as if the squid were eating. When you remove the beak you may see a long tube attached to it. This is the oesophagus, the food passes down the oesophagus to the stomach at the other end. Radula for scraping tearing and gripping prey.

3. Open the mantle Keep the squid on its back (the side opposite the funnel and dorsal fin). Using forceps, lift up the opening to the mantle behind the funnel (near the head) and separate the mantle from the internal organs. Cut along the ventral midline of the mantle, from its opening all the way to the tail. Be careful to keep the scissors lifted away from the internal organs so they are not damaged.

4. Reproductive Organs Female glands lay on top of the other internal organs. These glands create the gelatinous matrix that envelops the eggs. The male genital duct is a white, fluid-filled sac in the posterior end (back end) of the mantle. The sperm are stored in thin tubes in an elongated sac behind and along one gill.

5. Locate the gills. These are the long, feather-shaped organs that are attached to the sides of the mantle and extend along the anterior (front) half of the mantle. Identify the gill hearts, one on the posterior end of each gill (these are small, flat and white). Questions: Why are they white and our hearts are red or purple? The squid has a third heart (the systemic heart) that pumps blood to the rest of the body.

6. Digestive Tract (light brown) The long, silvery dark tube on top of the liver is the ink sac. Leave it for now. Locate the stomach and caecum. These lie together as one white, silky-looking tube, like a deflated bladder and a coiled sack. If you are curious about the liver, wait to cut it open until the end of the dissection. It contains a lot of brown, oily liquid which may obscure other organs. If possible, open the stomach and examine its contents. Many squid will have bits of partially digested crustaceans (pink and white pieces), or tiny fish scales and bones.

7. Observe the Ink Sac The silvery-black ink sac lies connected to the intestine. Be careful not to puncture it yet. Squid ink stains clothing and skin.

8. Remove the Gladius (Pen) The gladius is a long, clear feather-shaped structure used to support the mantle and for organ attachment. It and the cranium, or brain case, make up the "skeleton" of the squid. It feels like plastic and is made of tissue similar to a shrimp shell. Pry out the tail end of the gladius and pull straight back, away from the body.

8. (b) Write with ink and gladius Gently pierce the ink sac with the pen. Then, using only the ink-filled tip of the gladius, write your name on your squid illustration or paper. If the ink seems dry and pasty, add one drop of water at a time to create fluid ink. Squid ink was actually used to write and draw in ancient times.

9. Remove the eye lens If you carefully snip open the eye you can remove the hard lens with your fingers. It is round- human lenses are oval. Squid can tell the difference between light and dark, blue and yellow and forms a complete image of whatever it is looking at.

10. Remove the brain Go through the mouth with your tweezers and grasp the brain and the long nerve attached to it. Carefully remove and examine it.

Tentacle hooks and barbs of the Giant and Colossal Squid Hooks that can swivel 360° Barbs on a tentacle

This sperm whale was gouged by one or more colossal squid during its life time. This is judging by the deep scars on its head and the squid beaks found in its stomach. Computer animation

Suckers on a squid. Squid Suckers (have rings with teeth) Octopus Suckers (no hooks or hard rings) Suckers on a squid.

The Colossal Squid New Zealand fishermen have caught what is expected to be a world-record-breaking colossal squid. Fisheries Minister Jim Anderton said the squid, weighing an estimated 450kg,took two hours to land in Antarctic waters. Local news said the squid (Mesonychoteuthis hamiltoni) was about 10m long, and was the first adult colossal squid landed intact. One expert said calamari rings made from it would be like tractor tyres.

Colossal Squid Mouth and Beak

Size comparisons of squid