Halibut  (Hippoglossus vulgaris ), the largest of all the flat-fish and in form more elongated than the flounder or the turbot. The halibut, though esteemed for the table, is not to be compared in quality with the turbot; its flesh is white and firm, dry and of little flavor. It attains a great size; specimens have been caught weighing at least five hundred pounds, and one caught in Iceland was little short of twenty feet long.