EXCRETION. 



21. Flame cells of a Bilharzia miracidium seen under the '/ i Qcn oil-immersion 

 objective. 



22. Nephridial funnels of an annelid. Notice the beating of the cilia on the 

 nephrostome. 



23. Coelomic fluid of an earthworm under the microscope showing chloragogen 

 cells both whole and disintegrated, and leucocytes. 



24. Uric acid excreted by Argas. 



