LABRUS, in ichthyology, a genus of fishes belonging to the order of thoracici. The characters are as follow : The covers of the gills scaly ; the branchiostegous rays unequal in number ; teeth conic, long, and blunt at their ends ; one tuberculated bone in the bottom of the throat ; two above, opposite to the other ; one dorsal fin reaching the whole length of the back ; a slender skin extending beyond each ray, with a rounded tail. There are 41 species of this genus, which vary from each other, even those of the same species, almost infinitely in colour ; some of them being of a dirty red mixed with a certain duskeness ; others most beautifully striped, especially about the head, with the richest colours, such as blue, red, and yellow. Care must therefore be taken not to multiply the species from these accidental teints, but to attend to the form, which never varies. Mr Pennant mentions his having seen a species of labrus taken about the Giant's Caulway in Ireland, of a most beautiful vivid green, spotted with scarlet ; and others at Bandooran in the county of Sligo of a pale green. To this genus belongs the fish called by the English the old-wife.