The New International Encyclopædia/Hagfish

HAGFISH, or HAG (ME. hagge, hegge, from AS. hægtes, witch, MDutch haghetisse, OHG. hagazussa, Ger. Hexe, hag, witch; apparently connected with provincial Eng. hag, AS. haga, Dutch haag, Ger. Hag, inclosure, coppice). Any of several species of roundmouths (see Cyclostomi) that live parasitic upon fishes, and structurally are closely related to the lamprey (q.v.). They are eel-shaped in form and individuals of the genus Bdellostoma may reach a length of three feet. The common hag or ‘slime-eel’ (Myxine glutinosa) may grow to be eighteen inches long, and is found on both coasts of the North Atlantic south to Cape Cod. The mouth is formed by a mere membranous ring with a single tooth on its upper part, while the tongue is furnished with two rows of strong teeth, and also performs the office of a piston in the use of the mouth as a sucker. Around the mouth are eight tentacles. The skin is smooth and capable of secreting an enormous amount of mucus. There is only a membranous caudal fin. The eyes are very rudimentary and sunk beneath the skin. The six gill-pouches empty separately internally into the pharynx, but externally by a single tube. There are no bones; the skeleton is membranous and cartilaginous. The eggs are large, are inclosed in a horny case, and bear hooked processes at each end for attachment to weeds, etc. Myxine is hermaphroditic; the young animal produces sperms, and, later in life, ova. By means of the mouth the hags bore their way into the body of fishes, especially halibut and flounders, consuming them, leaving only the entrails, skeleton, and skin; hence another common name is ‘borer.’

The hag on the west coast of America (Polistotrema Stouti) is hated by the fishermen, because of its destruction of fishes caught in nets, and its ugly appearance. It is about fourteen inches long. See Plate of Lampreys and Dogfish.

HAGFISH (Myxine glutinosa).

1. Outline of the hag, showing: the two ventral openings (h) by which the water escapes from the gills. 2. Anterior portion of the body laid open on the ventral side to show the branchial sacs. æ, gullet laid open, showing on each side the six apertures by which the water is conducted to the corresponding branchial pouches (g); d, one of the efferent ducts by which the water is conducted away from the branchial pouches; cd, common efferent duct on the left side, opening on the ventral surface by a branchial pore (p or h of Fig. 1); gd, special canal developed on the left side only, and leading from the gullet into the common branchial duct; n, unpaired nostril, with its “barbels;” m, mouth.