Differential interference contrast (DIC) light micrograph of a Squantinella sp. rotifer. The wheel organ at right is covered by a broad bonnet. The bonnet and the wheel organ are not retractable. Two red eye spots are visible on the sides of the head. The tail of the animal is divided into two toes. Rotifers are multicellular aquatic dwellers. Squantinella rotifers are quite small and very fast swimmers. A Squantinella sp. green alga is on the left edge of the bonnet. Magnification: x800 at a print width of 10 centimetres.