"Diagrammatic sagittal section of Microstomum, showing a chain of four zooids produced by fission. b, brain of the original zooid (the exponents indicating corresponding structures of the more recently formed zooids); c, ciliated pit; d, dissepiments indicating different stages in the separation of the zooids; e, eye-spot; ent, entoderm; g, gut; gl., glandular cells about the mouth; m., mouth of the original worm." -Galloway, 1915

Microstomum

"Diagrammatic sagittal section of Microstomum, showing a chain of four zooids produced by fission. b,…