Rotifers (multicellular)

Philodina

Rotifers

there is a wide range amongst species size but around 25 µm - 1 mm.

Some species are planktonic, others are attached to plants, other organisms, stones or creeping on plants, mud surface etc.

Older books call them wheel animalcules. The head has a crown of cilia (the 'wheel organ'), which in some species looks as if it is rotating like a wheel.
Rotifer species show a wonderful variety of forms. Some move and contract like a leech (e.g. Philodina), others build 'houses'.

Classification :Kingdom - Animalia, Phylum - Rotifera