1. Class Polyplacophora
Chitons

2. Class Bivalvia
Dorsal
• Mercenaria
Anterior
adductor
muscle
Mantle Posterior
adductor
muscle
Ventral

3. Foot
Mantle
Cavity

4. Gills

5. Visceral mass

6. Mouth
Labial
palps

7. Heart

8. Excurrent
siphon
Incurrent
siphon

9. Digestive
gland
Gonad

10. Class Gastropoda
• nudibranchs

11. Subphylum:Trilobita
Trilobite

12. Subphylum: Chelicerata
Class: Merostomata
Limulus
mouth
chelate
Book gills

13. chelicerae

14. cephalothorax
Compound eye
abdomen
telson

15. Class Cephalopoda
Loligo
Systemic
heart

17. intestines

18. gills

20. Mantle
cavity dorsal
pen
gill
s

21. Siphon
retractor
muscle

22. Female Loligo
Ovary
Nidamental glands

23. anterior
Ink sac
Visceral mass
siphon
posterior

24. jaws radula

25. stomach
Buccal bulb
esophagus

26. mouth

27. collar