Aristotle's Lantern

Aristotle must have been an avid marine biologist; his History of Animals includes numerous descriptions of fish and shellfish, including the urchin, whose digestive system has become known as Aristotle's Lantern after this passage:

"…the urchin has what we mainly call its head and mouth down below,and a place for the issue of the residuum up above. The urchin has, also, five hollow teeth inside, and in the middle of these teeth a fleshy substance serving the office of a tongue. Next to this comes the esophagus, and then the stomach, divided into five parts, and filled with excretion, all the five parts uniting at the anal vent, where the shell is perforated for an outlet... In reality the mouth-apparatus of the urchin is continuous from one end to the other, but to outward appearance it is not so, but looks like a horn lantern with the panes of horn left out." (Aristotle, History of Animals, Tr. D'Arcy Thompson, courtesy of Wikipedia).