16 



Nils Rosén 



various. The coast shows all intermediate states between that of a low sand-beach 

 (Fig. E) to that of a steep rocky shore (Fig. D), but in all cases the ground is coral- 

 sand or such sand hardened to rock. Along the western side of Andros the ground 

 for a vast area consists of vtithe marl (Fig. F). As will be shown later on, different 

 formations of the fauna are found according to the character of the beach. Along 

 the shores coral reefs occur offerring, as always, great opportunities for various 

 types of animal life. The bottom of the sea, however, is uniform throughout the 

 whole archipelago, consisting only of coral-sand. Different depths are found, from 

 shallow water down to 1500 fathoms, as between the southern islands. 



There are two physical conditions more that are of great importance for the 

 study of the fauna of an oceanic island, the sea streams and the prevailing 



winds. The Bahamas are 

 swept both on the east and 

 on the west by the Antillean 

 Stream giving many oppor- 

 tunities for a passive tran- 

 sport from the Lesser Antil- 

 les and from Haiti and Cuba. 

 On the nortli runs the Gulf 

 Stream between the Baha- 

 mas and Florida, but the 

 direction of it makes it of 

 less importance in this re- 

 spect. It is possible that this 

 stream is able to transfer 

 animals from Cuba to the 

 Fig. G. Coppice (Mastic Pijint, Andros). Bahamas, but such a trans- 



portation from Florida to 



the Bahamas is hardly probable. The prevailing winds are easterly. The tracks of 

 the hurricanes, those terrible storms which are able to throw up on the beach rocks 

 weighing several tons, pass from the southeast over the Bahamas. From this it is 

 clear that a priori we have to expect that the fauna of the Bahamas has invaded 

 from south, from Cuba, Haiti or perhaps even from some of the Lesser Antilles. 

 An analysis of the fauna will be made, as far as it is possible to judge anything 

 from the present knowledge of it, in the following chapter. 



C. The Fauna of the Bahamas. 



It is quite impossible here to give a thorough account of the Fauna of the 

 Bahamas. Only a few classes of the animals found in the islands have so far been 

 the subject of investigations and the descriptions of them refer mostly to collections 

 made in an incidental or casual way. During my visit to the Bahamas I collected 



