Among these were diatoms, algae, protozoa, rotifera, and bacteria.
"The Home of the Blizzard" by Douglas Mawson
Quatrefage on the Rotifera, 487.
"Sketches of the Natural History of Ceylon" by J. Emerson Tennent
Nearly akin to them are the Snout-worms (Rhynchocoela), and the small microscopic Wheel-worms (Rotifera).
"The History of Creation, Vol. II (of 2)" by Ernst Haeckel