Proteomyxa, a group of the simple unicellular animals belonging to the great group of the Protozoa. Most of them live in fresh-water. The best-known members are the Monads and the Monera. They are all very simple in structure, and some appear never to have a nucleus, e.g. Archerina, so that they are "cytodes" and not "cells" (q.v.). Many of the Monera resemble simple types of the "Heliozoa" (q.v.), thus Archerina is much like the small "Sun-animalcule" or Actinoplvrys. Many of the Monads are parasitic; thus one species of Protomonas lives in the fresh-water Alga Spirogyra, and Colpodella in the minute Infusorian Chlamydomonas, or Gymnococcus fockei on diatoms. One group, the Plasmodiophoreae, lives in plant-roots: thus Plasmodiopkora brassiccc injures the roots of various species of vegetables of the genus Brassicci; it is the cause of the disease known as "Fingers and Toes." The members of this group, however, may be really vegetables, as they are assigned by most botanists to the Slime-Fungi or Myxomycetes. Bursulla, the only member of its family, lives on horse-dung. Our knowledge of the Proteomyxa is still very limited, and it is probable that when more is known the group will be broken up.