What are some examples of rotifers?

There are over 2,000 of rotifers and virtually every genus contains species with strange characteristics.

Most are females and very few are males. These "wheel animalcules" dates back nearly three centuries to their first description in 1703 by Leeuwenhoek.

Some examples are:

Euchlanis

Asplanchna (found in the Great Lakes)

and Conochilus (found in clean lakes and pounds and in colonies).

Nicely organized, nice pictures are on this site: http://www.ucmp.berkeley.edu/phyla/rotifera/rotifera.html