canthini, the position of which has much varied
in our classifications. Having no spines to their fins, the Gadids used,
in Cuvierian days, to be associated with the herrings, Salmonids, pike,
&c., in the artificially-conceived order of Malacopterygians, or
soft-finned bony fishes. But, on the ground of their air-bladder being
closed, or deprived of a pneumatic duct communicating with the digestive
canal, such as is characteristic of the Malacopterygians, they were
removed from them and placed with the flat-fishes, or _Pleuronectidae_,
in a suborder Anacanthini, regarded as intermediate in position between
the Acanthopterygians, or spiny-finned fishes, and the Malacopterygians.
It has, however, been shown that the flat-fishes bear no relationship to
the Gadids, but are most nearly akin to the John Dories (see DORY).

The suborder Anacanthini is, nevertheless, maintained for the
_Muraenolepididae_ Gadids and two related families, _Macruridae_ and
_Muraenolepididae_, and may be thus defined:--Air-bladder without open
duct. Parietal bones separated by the supra-occipital; prootic and
exoccipital separated by the enlarged opisthotic. Pectoral arch
suspended from the skull: no mesocoracoid arch. Ventral fins below or in
front of the pectorals, the pelvic bones posterior to the clavicular
symphysis and only loosely attached to it by ligament. Fins without
spines; caudal fin, if present, without expanded hypural, perfectly
symmetrical, and supported by the neural and haemal spines of the
posterior vertebrae, and by basal bones similar to those supporting the
dorsal and anal rays. This type of caudal fin must be regarded as
secondary, the _Gadidae_ being, no doubt, derived from fishes in which
the homocercal fin of the typical Teleostean had been lost.

About 120 species of Gadids are distinguished, mostly marine, many being
adapted to life at great depths; all are carnivorous. They inhabit
chiefly the northern seas, but many abyssal forms occur between the
tropics and in the southern parts of the Atlantic and Pacific. They are
represented in British waters by eight genera, and about twenty species,
only one of which, the burbot (_Lota vulgaris_), is an inhabitant of
fresh waters. Several of the marine species are of first-rate economic
importance. The genus _Gadus_ is characterized by having three dorsal
and two anal fins, and a truncated or notched caudal fin. In the cod and
haddock the base of the first anal fin is not, or b