HADDOCK (Gadus aeglefinus), a fish which differs from the cod in having the mental barbel very short, the first anal fin with 22 to 25 rays, instead of 17 to 20, and the lateral line dark instead of whitish; it has a large blackish spot above each pectoral fin - associated in legend with the marks of St Peter's finger and thumb, the haddock being supposed to be the fish from whose mouth he took the tribute-money.
Genera: Callionymus, Uranoscopus, Trachinus, Gadus, Blennius.
The genus Gadus is characterized by having three dorsal and two anal fins, and a truncated or notched caudal fin.
The cod, Gadus morrhua, possesses, in common with the other members of the genus, three dorsal and two anal fins, and a single barbel, at least half as long as the eye, at the chin.
COAL-FISH (Gadus vixens), also called green cod, black pollack, saith and sillock, a fish of the family Gadidae.
COD-LIVER OIL (Oleum Morrhuae, or Oleum Jecoris Aselli), the oil obtained from the liver of the common cod (Gadus morrhua).
POLLACK (Gadus pollachius), a fish of the family Gadidae, abundant on rocky coasts of northern Europe, and extending as far south as the western parts of the Mediterranean, where, however, it is much scarcer and does not attain to the same size as in its real northern home.
It is distinguished from other species of the genus Gadus by its long pointed snout, which is twice as long as the eye, with projecting lower jaw, and without a barbel at the chin.
In the shoal waters about Juan Fernandez are found a species of codfish (possibly Gadus macrocephalus), differing in some particulars from the Newfoundland cod, and a large crayfish, both of which are caught for the Valparaiso market.
WHITING (Gadus merlangus), a fish of the family Gadidae, which is abundant on the shores of the German Ocean and all round the coasts of the British Islands; it is distinguished from the other species of the genus by having from 33 to 35 rays in the first anal fin, and by lacking the barbel on the chin.