1. Earthworm Dissection
Lumbricus terrestris
Kingdom: Animalia
Phylum: Annelida

2. Students should Identify the
following
• Segments
• Septum
• Setae
• Pharynx
• Esophagus
• Crop
• Gizzard
• Intestine
• Aortic Arches
• Ventral Nerve Cord
• Dorsal Blood Vessel
• Clittelum
• Seminal Vesicles
• Seminal Receptacles

3. Students should know the following
terminology
• Invertebrate
• Castings
• Hermaphroditic
• Hydrostatic Skeleton
• Closed Circulatory System

4. Students will use the following tools
for the earthworm dissection
• Scalpel
• Scissors
• Probes – needle
• Dissecting Pins
• Rubber Padded Dissecting Tray

5. ScalpelScalpel

6. ScissorsScissors

7. Probe

8. Dissecting Pins

9. Dissecting Pan

10. Dissecting Language
• Anterior – FRONT
• Posterior – BACK
• Dorsal – UPPER
• Ventral – LOWER
• Cross Section – cut through an organism

11. Cross section

13. Before you start dissecting, find the
following:
• Mouth
• Setae – the bristles used for locomotion.
They are located by rubbing your fingers
along the earthworm’s body. They are
often times easier to feel than to see.
• Sperm Duct
• Clittelum

14. Mouth

15. Sperm Duct

16. Clittelum

17. Mouth
Pin your worm at the tip of
the mouth and at its
midpoint.

18. Start your incision 2 cm behind the
clittelum.
Make sure not to cut too deeply.
Continue your cut to the
mouth

19. Begin to separate
the skin using pins

20. Pin the skin back as
you go along the
cut. Angle your pins
outward so that are
out of the way.

21. As you pin the
skin back, take
your probe and
break the
partitions
between the
segments.
These are called
Septum.

23. Pharynx

24. Aortic Arches – Earthworms
have 5 pair of these simple
hearts.

25. Aortic Arch

26. Seminal Vesicles

27. Seminal
Receptacles

28. Crop

29. Gizzard

30. Dorsal Blood
Vessel
Intestine

31. Ventral Nerve
Cord

32. Ventral Nerve
Cord

33. Brain

34. Nerve Cord
and Brain

35. Brain