Protonephridium of a Shark Small 148×320 Medium 295×640 Large 473×1024 Download Tiff Original 1108×2400 | (618.4 KB) Description Structure of the protonephridium (excretory organ) of a shark. Labels: Wtr, ciliated funnels; Ug, segmental duct. Keywords "excretory system", annelid, protonephridium, worm Galleries Fish Anatomy Source: Beach, Fredrick Converse The Encyclopedia Americana (New York, NY: The Americana Company, 1903) Courtesy the private collection of Roy Winkelman
