1. BIOLOGY Unit 7: Crayfish Notes

2. (1) External Parts Carapace: Chelipeds: Maxillipeds: Swimmerets:
Hard, red outer shell
Exoskeleton to protect internal organs
Chelipeds:
Large pincher-claws
Used to grab prey
Maxillipeds:
Smaller arms near mouth.
Used to shove food into mouth.
Swimmerets:
Tiny, feather like legs (along belly)
Used to grasp during sex.

3. External Parts (Cont’d)
Antennae:
Long stalks along top of head.
Sensory reception.
Gills:
White, feathery like layers along sides of head.
Absorb oxygen from water (for breathing).

4. (2) In The Head Encephalon: Green Gland: Stomach:
Fleshy bit, Directly inside head, by eyes.
(Brain) Control all other organs + respond.
Green Gland:
2 small flesh-sticks on either side of eyes.
Secrete enzymes needed to digest food.
Stomach:
Sack full of bony teeth.
Directly behind head in center.
Breaks apart food.

5. (3) Chest & Abdomen Heart: Intestine:
Light brown flap behind stomach, along back.
Pump + circulate blood across organs.
Open Circulatory System = No blood vessels, organs bathe in blood.
Intestine:
Skinny tube leaving stomach.
Absorb nutrients and excrete waste.

9. Male Parts Appearance: Tiny, bent legs Location: Belly
Function: Insert sperm into female

10. Female Parts Appearance: Swollen hole
Location: Belly, in between swimmerets
Function: Take in sperm (like vagina)

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

12. External Dorsal:

13. External Ventral:

14. Sex:
MALE
FEMALE

15. External (Lateral):

16. Internal (Dorsal):

17. Deeper Internal (Dorsal):

18. Internal (Lateral)

19. Abdomen (Dorsal):