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In the rainy gloom of this early summer this large white slug gliding across the woodland floor could not go unnoticed. It would seem to be an unusual form of the usually dark grey leopard slug characteristically mottled with darker blotches. Specimens of that can reach 30 cms (one foot). This one was about twelve centimetres. Its food is generally rotting wood and leaves and toadstools. The leopard slugs have remarkably notorious mating habits. If you have seen David Attenborough's TV programme 'Life in the Undergrowth' or the description and illustration in his book of the same name you cannot forget it. Two slugs crawl, one following the other, in the wet weather, along a high branch in the trees. Since both are in the same body male and female (hermaphrodite) who is following whom would seem irrelevant. Then one forms a mass of thick heavy slime and deliberately drops from a branch some 30 centimetres, held on a rope of this mucus. The other follows adding to the mucus. They revolve round each other swinging from their trapeze. They both engorge their male sexual organs which flare out like parachutes, shining bluish white and much wider than the slugs themselves. These parachutes twist about on each other and fuse, with a process of sperm exchange taking place. After that, these remakable excrescences are reabsorbed and the slugs separate and find their way back to the tree. Bizarre, out-of-this-world, weird; such adjectives fit this performance.
All slugs have a large fold of flesh behind the tentacles. This fold is the 'mantle' and under it is a space used as a lung. The entrance to the lung is on the right hand side of the body. The nature of this mantle fold helps one to separate the slugs into two families. In most of the Limax family the fold is marked with ripples like a thumb print and the lung opening is towards the hind third of the mantle. In the other family (the Arion family) the mantle is covered in granules arranged in a haphazard manner and the opening is the middle of one side. Another major difference is that the slugs of the Limax family have a ridge or 'keel' along part or all of the back. All the body organs are confined to the region of the mantle. The sex and excretory openings are very close to the lung opening. The rear part of the creature is almost entirely composed of muscle. The tentacles carry the simple eyes. The mouth has a continually growing structure which is more or less a living file. It has a rough surface and with it the creature rasps away at its food.