118 BRITISH . Of the cod, which ranks first in commercial import¬ ance, there appears to be four kinds, although their history has not been sufficiently attended to, in order to determine their relations to each other as species or variety. The bank cod (which I will take upon me to class gadus bancus) frequents the great bank of ¬ land, and other banks at a great distance from land. It differs from the other species, in its not approach¬ ing the shores, its living principally on shell-fish, its body being larger and stronger, its colour lighter, its scales and spots larger, and its flesh firmer. The shore cod is nearly of the colour of the bank cod, and approaches the shores, and enters the har¬ bours, following the smaller fish on which it feeds. It resembles most the cod on the coasts of Britain, and it is of this kind that the greatest quantity is taken, at least during late years. The rock or red cod (gadus callarias) resembles, but is generally somewhat larger than, the rock cod or red-ware codling of Scotland . The seal-head cod, called so from its head resem¬ bling that of a seal, is the most remarkable and the most rare kind. Other differences are observed in the cod, which may arise from the peculiarity of the coasts they frequent. The livers of the cod farther north are smaller; and less oil is obtained from the bank cod, than from any of the other varieties. It has been « calculated that upwards of four hundred millions of cod are caught annually on the coasts of . 11