"B., one of the characteristic hollow flame-cells, leading into the excretory tubule (1), showing the long cili (2), the excretory globules (3), the nucleus (4), and pseudopodia-like processes (5) passing among adjacent cells." -Thomson, 1916

Plathelminth

"B., one of the characteristic hollow flame-cells, leading into the excretory tubule (1), showing the…