Allis shad Allis shad The allis shad ("Alosa alosa") is a widespread Northeast Atlantic species of fish in the herring family, Clupeidae. It is an anadromous fish which migrates into fresh water to spawn. It is found in the eastern Atlantic Ocean, the western Baltic Sea and the western Mediterranean Sea. In appearance it resembles an Atlantic herring but has a distinctive dark spot behind the gill cover and sometimes a row of up to six spots behind this. It sometimes hybridises with the twait shad ("A. fallax"). This fish becomes mature when three or more years old and migrates to estuaries,
Subterranean river many cities there are natural streams which have been partially or entirely built over. Such man-made examples of subterranean urban streams are too numerous to list, but notable examples include: Some fish (popularly known as cavefish) and other troglobite organisms are adapted to life in subterranean rivers and lakes. Greek mythology included the Styx, Phlegethon, Acheron, Cocytus, and Lethe as rivers within the Underworld. Dante Alighieri, in his "Inferno", included the Acheron, Phlegethon, and Styx as rivers within his subterranean Hell. The river Alph, running "Through caverns measureless to man / Down to a sunless sea" is central to the