Squid
Dissection & Octopus Arms Lab
by Liz LaRosa
www.middleschoolscience.com
Objectives:
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To observe the external and internal anatomy of a cephalopod.
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To compare and contrast tentacle and arm designs of a squid and octopus.
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To write your name in squid ink!
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To examine the squid’s eye
Procedures:
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Examine the outside of the squid. Label the
tentacles, head, eyes, mantle and fins
into Figure 1.
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Look at the squid's mouth. Remove the beak.
Touch and examine the beak.
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Try to see how the jaws work together.
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Go through the mouth with your tweezers and
grasp the brain and the long nerve attached to it. Carefully
remove and examine it.
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Turn the squid over and lay it flat. Carefully
cut through the mantle only. Lay the mantle open.
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Using the squid diagram sheet for reference,
find and examine: the food tube, liver (pale brown), stomach
(glistening, white), gill (feathery) and hearts. Place in
Figure 2.
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Find the silvery, black ink sac.
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Locate the hard pen near the squid's
fin end. Grasp the pen and pull it out!
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Gently pierce the ink sac with the pen. Write
you name using the ink into Figure 3.
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Remove the eye from the squid and examine it.
Remove the cornea (film like), and the lens (hard, silvery
pearl-like structure) Label and sketch into Figure 4.
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Compare the Squids tentacles to the Octopus arms.
Note the shapes, sizes and textures, and sketch into Figure 5:
Data: (Leave
½ page per figure in notebook)
Figure 1: External Anatomy of
the squid with labels
Figure 2: Internal Anatomy of Squid
with labels
Figure 3: Writing my name in squid
ink!
Figure 4: Squid Eye with labels
Figure 5: Octopus arms
Analysis:
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How many tentacles are there?
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Look at the suction cups. How many tentacles
have them?
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How many tentacles do not have suction cups?
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Describe how the pen looks and feels.
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What do you think is the purpose of the pen?
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Compare and Contrast the tentacles of the squid
and the arms of the octopus. List 2 difference and 2 similarities.
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How is the squid’s eye similar to ours?
Conclusion:
2-3 sentences on what you learned
DID YOU LABEL EVERYTHING?
FYI: Octopus arms are sometimes called tentacles by mistake
TEACHER'S
NOTE: (This is just my personal opinion and experience.)
I would NOT buy the squid from the biological supply companies, they are too
big, hard to manage and cut. I buy my squid from the local supermarket,
they come in 3 lb frozen boxes and are about 5 inches long and very
inexpensive. Defrost them overnight. I use one squid per group of
3-4, but you can have one for every 2 people as well. Your classroom will
smell like a fish market for the day, but its worth it! This is one
my favorite labs of the year!
This Lab was modified from
its original version at: www.antioch.k12.ca.us/kimball/Squid/squidintro.htm
