Help to identify critteres plz

[smiledd]

They are all snails, as I understand. Are they harmless? =)
1. Imageshack - img1261q and Imageshack - img1269j nickel size
2. Imageshack - img1264n and Imageshack - img1267lu nickel size
3. Imageshack - img1262g smaller than a dime
4. Imageshack - img1272s dime size

[smiledd]

Ok #3 is a Limpet =)

[zhenya]

Ok #3 is a Limpet =)

#4 most likely a Cerith sp.

PS. Not sure if your limpets are harmless, depends alot on a species and to identify a snail to species level you need different images. The Ceith species are indeed harmless.