This is a fast-moving and very small creature, found in a water container in the garden of a house in Northumberland Avenue, Aldersbrook. It looked like some sort of sting-ray-shaped jet aircraft, and at first it was thought that the shape was something of an optical illusion created by its speed. It was thus thought to be a Brine Shrimp - Artemia salina - but was certainly not in the salt water it required. Only later was the apparent true identification was a free-swimming ciliate - Caenomorpha medusula.