Water tube
- One of a system of tubular excretory organs having external openings, found in many invertebrates. They are believed to be analogous in function to the kidneys of vertebrates. See Illust. under Trematodea, and Sporocyst.
The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.