1. Crayfish Pre-Lab

2. External Structures

3. Carapace Appearance: Hard outer shell Location: Exterior of the body
Function: Tough exoskeleton made of chitin; protects internal organs

4. Antennae Appearance: 2 long stalks Location: Front of head.
Function: Sensory reception.

5. Chelipeds Appearance: Large pincher-claws
Location: Anterior end; near the head
Function: Used to grab food and for defense

6. Walking Legs Appearance: Long, thin legs
Location: Ventral (belly) side, mid section
Function: Movement

7. Swimmerets Appearance: Tiny feather-like legs
Location: Ventral (belly) side near posterior
Function: Help with swimming + grasping during mating

8. Uropods & Telson Appearance: Fan-like tail
Location: Posterior (rear) end
Function: Propel during swimming.

9. Mouth Appearance: Tiny lips Location: Front of head/anterior
Function: Eating, intake of food

10. Maxillipeds Appearance: Tiny claws Location: Under head and Chelipeds.
Function: Bring food to mouth.

11. Internal Structures

12. Brain Appearance: Fleshy piece
Location: Directly inside head, by eyes.
Function: Controls organs + responses.

13. Digestive Glands Appearance: Light yellowish masses
Location: 1 on each side of head behind eyes
Function: Secrete enzymes needed to digest food. Also called “green glands”

14. Stomachs Appearance: Fleshy light gray sacks
Location: In between digestive glands
Function: Grind up food (uses teeth-like structures).

15. Heart Appearance: Light brown lobe/flap.
Location: Behind stomach + digestive glands
Function: Pump + circulate throughout body

16. Intestine & Anus Appearance: Skinny tube + posterior opening
Location: Leaving stomach, going down back.
Function: Absorb nutrients + carry waste out of body.

17. Gills Appearance: White colored feathers
Location: Sides of head, under shell.
Function: Gas exchange (oxygen and CO2).

18. --Dissection Notes-- Lay crayfish on its belly.
Find carapace behind head.
Cut along lines + gently remove carapace.
Identify internal + external organs.

19. Virtual Dissection… https://www.youtube.com/watch?v=2cBGuEDxvNo

20. Internal (Dorsal):

21. Deeper Internal (Dorsal):

22. Internal (Lateral)

23. Abdomen (Dorsal):