1894. PEOCEEDINGS OF THE NATIONAL MUSEUM. 439 



species, one each iu Cuba and Haiti, while neither of the genera are 

 fonnd in Jamaica, appears to favor a more northern as well as a southern 

 laudway. 



RELATIONS OF THE GREATER ANTILLEAN LAND SNAIL FAUNA WITH 

 THAT OF THE BAHAMAS. 



I next pass to the relationship of the land snail fauna of the Greater 

 Antilles with that of the Bahamas. - On this extensive archipelago, 

 with some 3,000 islands and an area of nearly G,000 square mdes, there 

 are only about 80 species of land snails known. The climate of the 

 islands is warm, the structure of most of them is coral limestone, and 

 there is a plentiful rainfall, with sufficient vegetation to furnish shelter 

 and food for an abundance of snail life ; in fact the number of individ- 

 uals is in many cases great. All the groups with the exception of the 

 Mexican genus Schasichcilus, represented by a single species, are Cuban 

 and IJaitien, or are such as are found in those islands; aiul a number, 

 of the species are common to the Greater Antilles. In many genera, 

 especially Hemitrochus and Cerion, th«^re is an almost endless amount 

 of variation, with few breaks sufficient for the proper separation of 

 species. The islands of the Little and Great Bahama Banks being 

 nearest to Cuba, and lying in the course of the currents that tiow by 

 that island, partake most largely of its fauna, while those to the north 

 of Haiti bear more strongly the impress of its forms. Yet when we come 

 to carefully consider the manner in which this archipelago must luive 

 been colonized with land snails, we need not be surprised at its com- 

 parative poverty of species, or that it has no peculiar genera. Whether 

 in time past this area arose above the sea and had land connection 

 with Cuba and Florida does not matter so far as its present terrestrial 

 niolluscan fauna is concerned. As the highest point in the archipelago 

 is only about 300 feet above sea level it is quite probable that the entire 

 Bahamau region was submerged during the general period of subsid- 

 ence, and whatever species may have existed were doubtless destroyed. 

 We may suppose that during the period of elevation which followed, 

 as soon as these islands began to appear above the sea, and were titted 

 for the abode of land snails, those nearest to Cuba, Haiti, and the gulf 

 stream received occasional stragglers which drifted across the not very 

 Avide channel.* 



*The uorth-east trade wincLs, and the drift of the water of the Atlantic to the 

 "westward, force a strong current along between Haiti and the small, sonthernmost 

 islands of the Bahamas. Part of this is carrioil through the windward ])assage 

 between Haiti and Cuba into the Caribbean, the rest is pressed on past Great Inagiia, 

 and up the old Bahama Channel, and finally it mingles with the gnlf stream. No 

 doubt ])art of the watsT of that great ocean river, crowded in l)etween ('uba, the 

 Bahama Bank, and Florida, spreads out more or less to the eastward among the 

 islands. Tims land snails washed into the sea on the north side of Cuba or Haiti 

 would proba))ly in some cases be carried out and landed anmng the Bahamas. 



