Start here: Slug or Snail?
- no visible shell or a small shell that cannot contain their body.
- a coiled shell that can contain most or all of their body.
Parts of a slug
Common slug identification key
- Slug has no visible shell and has...
Slugs with anterior pneumostomes
1. No line where tail can be shed. Caudal pore present. Body tubercles uneven, ovoid in shape with no apparent pattern.
2. Line where tail can be shed (can be difficult to see). This can be an impressed line or indicated by a change in the skin texture. No caudal pore. Body tubercles typically diamond shaped in diagonal rows.
Slugs with posterior pneumostomes
1. With bands or spots and...
...foot fringe with vertical stripes, mantle without wrinkles -
2. No bands or spots (may have pigmented speckles) and...
3. Mantle with wrinkles centered on pneumostome. Keel 1/3 tail length or less - Deroceras sp.
4. Mantle appearance...
...with U-shaped groove. Foot fringe without vertical stripes. Less than 70mm (2.75”) - Milax gigates