Snails

The anatomy of an aquatic snail with a gill, a male prosobranch gastropod. Note that much of this anatomy does not apply to gastropods in other clades.
Light yellow - body
Brown - shell and operculum
Green - digestive system
Light purple - gills
Yellow - osphradium
Red - heart
Pink -
Dark violet -
1. foot
2. cerebral ganglion
3. pneumostome
4. upper commissure
5. osphradium
6. gills
7. pleural ganglion
8. atrium of heart
9. visceral ganglion
10. ventricle
11. foot
12. operculum
13. brain
14. mouth
15. tentacle (chemosensory, 2 or 4)
16. eye
17. penis (everted, normally internal)
18. esophageal nerve ring
19. pedal ganglion
20. lower commissura
21. vas deferens
22. pallial cavity / mantle cavity / respiratory cavity
23. parietal ganglion
24. anus
25. hepatopancreas
26. gonad
27. rectum
28. nephridium