"A colonial flagellate Infusorian--Proterospongia haeckelii. There are about 40 flagellate individuals. a, nucleus; b, contractile vacuole; c, amoeboid unit in gelatinous matrix; d, division of an amoeboid unit; e, flagellate units with collars contracted; f, hyaline outer membranes; g, unit forming spores." -Thomson, 1916

Infusorian

"A colonial flagellate Infusorian--Proterospongia haeckelii. There are about 40 flagellate individuals.…