THE ANNULARIIDAE OF THE BAHAMAS 



The Bahamas constitute an archipelago of islands forming an arc 

 with a southeast-nortliwest trend. The southeastern limit, Navidad Bank, 

 lies about 30 miles off northeastern Dominican Republic. Its western- 

 most confines embrace the Cay Sal Bank, which lies about 25 miles north 

 and a little west of the center of the north coast of Cuba. On the west 

 the broad and deep Gulf Stream separates them from Florida. The 

 northern limit of the Bank falls in latitude 27° 25' N., or about opposite 

 Indian River Inlet, Fla. On the east the Atlantic Ocean sets a limit 

 to the group. The Bahamas are separated from Hispaniola and Cuba 

 by the profound Bahama Channel. 



We are told that this immense territory embraces a dry land area 

 of some 4,404 square miles, consisting of 29 inhabited islands, 661 cays, 

 and 2,387 rocks. From an ecologic standpoint there is much uniformity 

 both in substrate environment and in climate. 



The northern part of the archipelago consists of a number of shal- 

 low banks from which the comparatively low island and cays project. 

 The northernmost of these is the little Bahama Bank, upon which 

 Bahama Island, Little Abaco, and Great Abaco are situated. This part is 

 separated from the region to the south by Northwest Providence Chan- 

 nel and the Tongue of the Ocean ranging from 250 to 2,250 fathoms in 

 depth. 



To the south of this lies the Great Bahama Bank, which has a shallow 

 sea of a few fathoms depth, extending for more than 50 miles west- 

 ward from the Berry Islands chain and Andros Island. On the north- 

 western border of this flat Bimini and Gun Cay harbor land mollusks. 



Andros Island, about 95 miles long, forms the western limit of the 

 Tongue of the Ocean, a profound cul-de-sac erosion channel that finds 

 its exit in the northeast Providence Channel. The region south of 

 Andros and the Tongue of the Ocean is a continuation of the shallow 

 sea, which bends northward on the east of the Tongue of the Ocean and 

 bears, in addition to a few cays on the western margin, a chain of cays 

 on its eastern border that extend from South Point, Long Cay, north- 

 westward for a distance of about 200 miles to New Providence Island 

 and beyond this to northeastern Eleuthera, then southeast to Cat Island 

 where it forms the Atlantic barrier, a chain of islands about 125 miles 

 long. This chain is separated from the Long Key-New Providence axis 

 by the deep Exuma Sound, which in places is more than 1,000 fathoms 

 in depth. 



With very little shift in ocean levels, much less than took place 

 through the abstraction of water to form the ice cape during the glacial 

 period, all this area would emerge from its watery covering and enable 

 land animals to move over the entire area dryfooted. The affinity of our 

 mollusks bespeaks such a state of affairs. 



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