Biology Dissection Lab 9.3
Name: _______________________
Lab Number: 9.3
Date:_________________
Crayfish Dissection
Supplies:
● Dissection tray and kit
● Gloves
● Crayfish specimen
Purpose: To become more familiar with the crayfish’s anatomy through dissection
Procedure:
Exterior
1. Examine specimen and
identify the exterior
features.
2. Turn the crayfish ventral
side up on the
dissection tray and
examine the
mouthparts.
Dissection
1. Use your forceps to remove all of the mouthparts from one side of the crayfish.
2. Lay them on the dissecting tray side by side to examine their relative sizes.
3. Determine the gender of your crayfish.
4. Place your specimen dorsal side up and use scissors to cut the crayfish’s carapace from
the posterior end of the carapace to just behind the eyes.
5. Make a transverse cut just behind the eyes.
6. Carefully remove the carapace and the two pieces determined by your cuts.
7. Examine the structure of the gills.
8. For ease, pull off the walking legs.
9. Carefully remove the internal tissue on the dorsal side of the crayfish.
10.Locate the structures listed below and check off when you identify them.
11.Cut open the abdomen to reveal the intestine.
12.Cut the dorsal side of the abdomen exoskeleton from the anterior end to the telson.
13.Open the abdomen.
14.Follow the intestine forward to find the stomach.
15.Draw crayfish as it looks now. Label all structures.
16.Remove some of the internal organs.
17.Pull the stomach so you can reach under it with your knife or probe and cut the
esophagus.
18.Pull the stomach and intestine out.
19.Look for the green glands just posterior and below the antennules.
20.Look for the brain.
21.Try to trace the nerve cord from the brain to the abdomen.
22.Draw the crayfish as it appears now. Label structures you were able to find.
23.Clean up.
Observations and Drawings:
Exterior Structures Observed:
Mandibles
Maxillae
Maxillipeds
Internal Organs Observed:
Heart
Gonad (m/f)_____
Digestive Glands
Brain
Green Glands
Comments:
Internal Crayfish
0
