The Sea Hares - Family Aplysiidae

THE SEA HARES - FAMILY APLYSIIDAE Genus APLYSIA, Linn.

I

met a sea hare first on the border of a coral key in southern Florida. The strange-looking object was about six inches long, a mass of mottled purple jelly, tapering to a point behind, extend ing forward into a small, erect head on a long neck. Two pointed wing-like flaps met over the back. Two flexible prongs stood out from the head and two smaller one from the neck. The creature swam gracefully among the seaweeds, using as propellers the broad side flaps. I ventured to capture this interesting stranger in a crab net, whereupon the surrounding water was dyed purple in an instant.

This is a reasonable defence of an animal whose shell is nothing but a transparent, flexible rudimentary plate, hidden in the soft back. Under the shell is the gill, to which water is brought by a siphonal fold of the mantle. The head is like a hare's, when seen in front.

At different ages the sea hare lives at different depths, closely imitating in colour the seaweeds and anemones upon which it feeds. When adult it has passed through several zones,

and takes the liberty of ranging backward to shallower water. At breeding time the creatures flock together. The eggs are laid among seaweeds in gelatinous, thread-like cases.

The name Aplysia means indelible. The fluid emitted was once believed to be a poison, killing even the person who touched the animal with a stick. The Mediterranean A. depilans was charged with causing baldness, by a form of absent treatment. It is known now that they are all harmless creatures; the natives of the Friendly and Society Islands use kindred species for food, preferring to eat them raw.

246 The Shell-bearing Sea Slugs A. Californica, Coop., rarely cast ashore by storms on the west coast, reaches fifteen inches in length.