Who'd be a snail?
The pelican, for example, represents devoted and self-sacrificing charity.
The gannet, which modern day simile represents as greedy, is a creature which subsists by the wings of his virtue and merit, having little land to rest upon. I'll never steroetype gannets again.
The raven is one who,having derived little from his ancestors, has through providence become the architect of his own fortunes or one of an enduring constancy of nature.
The Dolphin represents charity and a kind affection towards children, and is still seen as a benign force today, I think.
Mermaids represent eloquence. Though, personally, I've never heard a memorable quote attributed to a mermaid. Please correct me if I'm wrong.
The scallop shell represents one who has made long journeys or voyages to far countries, who had borne considerable naval command, or who had gained great victories.
Finally, we have the snail, which stands for deliberation and perseverance. Now, I have no doubt that these are admirable qualities, but it's not going to make for a very impressive coat of arms, is it? I mean, we have Richard The Lionheart, with his impressive symbolism, but I doubt he'd have a lot of people rallying to join The Crusades if he was Dickie The Snail. Actually, that may not have been a bad thing...
With many thanks to this site which references W. Cecil Wade's "The Symbolisms of Heraldry or A Treatise on the Meanings and Derivations of Armorial Bearings". Published in London in 1898.