IN contrast to the somewhat commonplace, perhaps almost dull, appearance of worms living on land or in fresh water, those living in the sea are often remarkable for their beauty and the unusual forms they assume. Many are brightly and variously coloured, others are luminous. Some burrow in the sand, others swim about habitually, and yet others build homes of sand or mud which in themselves are interesting objects for study. Perhaps the most remarkable of all the marine worms is that which goes by the name of Aphrodite, or the Sea-mouse, and which may be seen, often in large numbers, on the sandy beaches around the shores of the British Isles.
The body of a Sea-mouse is four inches or so long and nearly two inches across at the centre, and from there tapers away to end in a rounded head and tail. The animal creeps about over the sand with the smooth and easy movement characteristic of a mouse. Its upper surface is covered with a pile of fine bristles which change colour with the movement of the animal’s body and gives the impression of being a coat of iridescent fur. This strange beast, often seen on a sandy shore as the tide is going out, is sometimes the cause of considerable speculation as to what it really is. If, however, we turn it over on to its back all doubt and guessing is put at rest. The under surface is ringed in exactly the same way as the body of the common earthworm, and there too are the pairs of brisdes of which mention has already been made. In fact, the Sea-mouse is merely a worm whose body has become much enlarged and in which the upper surface has become obscured by a dense coating of bristles similar to those used by all worms as organs of locomotion.