GEOGEAPHICAL DISTEIBUTION of the GADIDiE. 543 



the OadUicc need not traverse the icy Arctic current ; they have but to 

 seek for the cool and fresh water of the bank. Adding to this that the 

 distance from Greenland and Iceland is about 200 or 300 geographical 

 miles, while from the Northern Fucus Bank to the Bank of Newfound- 

 land it is but 100 miles, it is therefore more natural that the fishes 

 migrate from the Fucus Bank than from Greenland and Iceland. If 

 the Fucus Bank were scientifically examined, we should obtain certainty 

 in regard to this question. 



The two parts of the Arctic Gadidce region are separated, from the 

 mouth of the Indigirka to Behring Strait on the one side, and from 

 the mouth of the Mackenzie and Beechey Island on the other. Proba- 

 bly these two parts diffuse through the depth and unite at the Behring 

 Strait, and through it spread into the Pacific Ocean, along the American 

 and Asiatic coast ; for some Gadidw of the Arctic type are met with in 

 the northern parts of the Pacific. The abundance of individuals is very 

 great on the two opposite coasts. 



D.— THE ATLANTIC REGION OF THE GADID.^. 



The Atlantic region of the Gadidce comprises the sea extending along 

 the eastern shores of North America from Nova Scotia to the 35th 

 parallel ; Cape Hatteras ; from there in an easterly direction to the 

 Azores by way of the Fucus Bank, extending as far north as Great 

 Britain; the German Ocean and the Baltic, and south through the 

 Mediterranean Sea as far as the Black Sea, and by way of Madeira to 

 the South Canary Islands. We are unfortunately not acquainted with 

 the fish fauna of the Bermuda Islands and the Azores, but it is probable 

 that here, too, some Atlantic forms of this widely-spread family will be 

 found, as they occur very frequently near Madeira. 



The Fucus Bank divides the region into two uneven parts, the Atlan- 

 tic region of the Gadidw, extending east and west of this bank. The 

 western ])art, along the coast of North America, is the smaller of the 

 two. South of Nova Scotia, as far as Philadelphia and Cape Hatteras, 

 we find only 4 genera with 9-10 species, northern and southern fish liv- 

 ing together within a small space. 



East of the Fucus Bank the Gadidw fauna changes very suddenly, ex- 

 hibiting greater variety of form, size, and mode of life. In the north, we 

 begin with the Scandinavian Gadidce. Near the Scandinavian and the 

 Cimbric peninsulas, the Danish Islands, and in the seas surrounded by 

 these countries, there is a very rich Gadidce fauna, rich not so much in indi- 

 viduals as in genera and species. According to Nilsson's account, of 

 1855, we find here 4 genera, with 17 species, but, according to more recent 

 accounts, 8 genera, with 18-19 species. Souther»Scandiuavia and Den- 

 mark have, besides many northern varieties, genera and species of the 

 Gadido], which never occur as far north as Finmarken, Iceland, and the 

 Faroe Islands. 



