• 12 parts
  • Checked September 2026

Label Mollusk Body Plan Diagram

Twelve numbered parts on the textbook mollusk, with a blank line for each and a key.

Label Mollusk Body Plan Diagram

Name Date

Numbered worksheet

1 2 3 4 5 6 7 8 9 10 11 12
More options

Write the name of each numbered part.Answer key

  1. Shell
  2. Mantle
  3. Foot
  4. Head
  5. Mouth
  6. Radula
  7. Visceral mass
  8. Stomach
  9. Heart
  10. Mantle cavity
  11. Gills
  12. Anus

Drawn for this site on 2026-09-30 from plain geometry. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Read every name on the labeled mollusk

All 12 parts on the diagram

Show the list

Outside 5

  1. Shell The hard cover over the back. The mantle lays it down and strengthens it with calcium carbonate.
  2. Mantle The sheet of body wall that covers the back. It makes the shell, and at the rear it hangs down to roof over the mantle cavity.
  3. Foot The broad muscular underside. Different mollusks use it for creeping, for holding on to a rock or for burrowing.
  4. Head The front end of the animal, which carries the mouth.
  5. Mouth The opening at the front of the head, where food goes in.

Inside 7

  1. Radula A ribbon of tiny teeth inside the mouth. It is used to rasp food off a surface. Snails and squid have one. Clams and mussels do not.
  2. Visceral mass The hump of soft organs above the foot. These are the gut, the heart, the kidneys and the rest.
  3. Stomach The widest part of the gut. Food comes to it from the mouth, and the intestine leads on from it to the anus.
  4. Heart A small pump high in the visceral mass, in its own space. It pushes blood out among the organs.
  5. Mantle cavity The space under the mantle at the rear. Water flows through it over the gills, and the anus and the kidneys empty into it.
  6. Gills Take oxygen from the water flowing through the mantle cavity. Comb-shaped gills, called ctenidia.
  7. Anus The end of the gut. It opens into the mantle cavity, so the water leaving carries the waste away.

How this list was compiled: Every name checked on 2026-09-30 in two sources. Wikipedia, Mollusca, Radula, Mantle and Ctenidium, https://en.wikipedia.org/wiki/Mollusca. University of California Museum of Paleontology, The Mollusca, https://ucmp.berkeley.edu/taxa/inverts/mollusca/mollusca.php. R. W. Hegner, College Zoology (1912, public domain), https://archive.org/details/collegezoology00hegn. H. S. Pratt, A Course in Invertebrate Zoology (1902, public domain), https://archive.org/details/courseininverteb00prat. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work

How it works

To label the mollusk body plan diagram, write a name on the line for each number. Numbers 1 to 5 are the parts that show from outside, shell to mouth; 6 to 12 are inside the body.

Read the full guide

Word bank for the mollusc label worksheet

Twelve names, in alphabetical order: anus, foot, gills, head, heart, mantle, mantle cavity, mouth, radula, shell, stomach, visceral mass. The paper prints no word list.

The numbers that get swapped

1 and 2 are both at the top: 1 ends on the outer arch, the hard cap, and 2 on the band of skin under it. 5 is the dark opening at the very front, 6 the toothed strip behind it. 7 ends in the plain part of the hump; 8 and 9 are organs inside it, the large bag toward the head and the small one high at the rear. At the rear, 10 ends in the open space, 11 on the comb and 12 on the dot where the tube stops.

  • When marking, pallium is right on line 2, visceral hump on line 7, pallial cavity on line 10 and ctenidia on line 11.
  • No number: the stalk and the dot on the head, a tentacle and an eye, and the intestine, the tube from 8 to 12.

Questions and answers

What is the hypothetical ancestral mollusc?

The textbook name for the made-up animal on this worksheet, also called the generalized mollusc or archi-mollusc. It has a single cap-shaped shell on top and a single muscular foot underneath, and it looks rather like the living monoplacophorans.

Which animals are mollusks?

Snails and slugs, the gastropods, make up about 80 percent of the known species. Clams and other bivalves are mollusks, and so are squid and other cephalopods, the chitons and the tusk shells.

How does a clam differ from the mollusk body plan?

A clam has a hinged pair of half-shells where the plan has one cap. It has no head and no radula, so numbers 4 and 6 have nothing to match. Its mantle, foot, gills, stomach and heart are all there.

What does the word mollusk mean?

Soft. Mollusk and mollusc both come through French from the Latin mollusca, which is from mollis, soft. Mollusks are invertebrates, animals without a backbone.

Does the mollusk worksheet have an answer key?

Yes. The key prints the same numbered drawing over the twelve names in order, shell first and anus last.

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