Marine Biology
Squid Dissection Lab
Student name:
_______________________________
8th grade Science
Lab date: ___________________________
Lab report due date __________________________
Background information
Do NOT copy and paste, these should be your words summarizing what the reader needs to
know about the squid to make this dissection valid (150 words or more). Use the files available
in MOODLE: Classification Mollusc and Squid Introduction.
Marine Biology- Squid Dissection Lab
Objectives
 Dissect a squid and identify the organs and major organ systems of the squid.
 Determine the function of various squid structures.
 Describe features of the squid that are characteristic of phylum Mollusca.
Materials
 Squid
 Dissecting scissors
 Dissecting pan
 Dissecting pins
 Hand lens
 Goggles
Safety
Read the lab; list at least 2 safety procedures
1.
2.
Procedures
Read and initial each Part for Pre-Lab.
Read and initial each Part on Lab day.
Part A. Body Organization
1. Place the squid on the dissecting pan. Note
that there is no external shell and that the
major part of the body is enclosed by the soft,
muscular mantle. There are ten conspicuous
arms, or tentacles, derived from the mollusk
foot.
2. Arrange your specimen so that the mantle
points away from you. Turn the animal so that
the siphon faces you. The eyes should be on
the right and left sides of the body.
3. Slit open the mantle cavity by inserting the tip
of the scissors under the mantle at the siphon
Marine Biology- Squid Dissection Lab
and cutting to the pointed end of the mantle. Cut with care so that you do not disturb
the internal organs.
4. Pin down the mantle to the pan, slanting the pins at an angle away from the specimen.
Part B. Mantle Cavity and Respiratory System
1. Examine the mantle cavity. The walls of the mantle
cavity are very muscular. The cavity is involved in
propelling a squid through the water. In the living
squid, the mantle cavity expands by muscular action
and fills with water. Find the collar. The collar locks
tightly against the head, leaving the siphon as the
only exit for water. The mantle muscle then contracts
and water is squeezed out through the siphon. This
method of movement is referred to as jet propulsion.
2. Examine the siphon. The siphon is well-equipped
with muscles and can be pointed for directional jet
propulsion. Note the muscular valve.
3. Find the two gills. These structures are orientated so
that incoming water passes over them.
4. Locate and remove the pen.
Part C. Feeding and Digestive Systems
1. Examine under a hand lens the structure and organization of the suckers. The
suckers, which are located in the tentacles, are used to hold prey.
2. Remove the siphon and with scissors make an incision into the head. Expose the
beak. Pry open the beak and observe the tongue like radula. Trace the esophagus,
which is surrounded by the liver, to the thick walled stomach. The stomach emerges
to form the caecum. Note the pancreas. The intestine runs from the stomach and
terminates at the rectum. An ink sac arises from the intestine near the anus. The ink
sac is used for defense.
Marine Biology- Squid Dissection Lab
Part D. Circulatory, Excretory, Nervous, and Reproductive
1. Locate the systemic heart. This is a difficult structure to find because it is
transparent.
2. Examine the nephridium, a kidney like excretory organ that removes waste products
from the blood.
3. Locate the white mass of the cranium above and between the eyes. The structure
contains the squid’s brain.
4. Locate the reproductive organs. Determine the sex of your squid. The male has
testes that lie beneath the caecum. The female has two large nidamental glands that
secrete protective covering over the eggs. Eggs might be present.
5. Remove the eye and cut it in half. Examine the transparent lens and the shiny black
retina at the back of the eye.
Marine Biology- Squid Dissection Lab
Data and Observations
One lab member will be the recorder. Data and observations will be shared between the lab
members.
Organ
Function and Observations
Mantle
Siphon
Gills
Suckers
Pen
Ink Sac
Nephridium
Nidamental gland
Marine Biology- Squid Dissection Lab
Analysis/ Conclusions
Use complete sentences and complete thoughts for ANY credit.
1. Describe squid locomotion.
2. What anatomical features show that a squid is well- adapted to a predator existence?
3. What could be the advantage of a reduced internal shell?
4. Cephalopods are thought to have the most highly developed eyes in the invertebrate world.
What anatomical evidence did you see that indicates this?
5. Which features of the squid are common to all members of the phylum Mollusca?
6. Study the diagrams. On Thursday 05/23, be prepared to label the following parts: mantle,
siphon, tentacles, eye, gill, pen, suckers, and systemic heart.
Marine Biology- Squid Dissection Lab