88 THE BERMUDA ISLANDS. 



transported by vessels, or even through the agency of birds. 

 The interesting question here naturally presents itself: Of 

 what relation to the Bermudian fauna are the two or three 

 identical species — Helix ventricosa, H. pulchella, and Csecilianella 

 acicula — which occur in the East Atlantic islands (Azores, 

 Madeira, Canaries) and Europe ? Are they a part of the west- 

 ern fauna which has gradually drifted eastward, and stocked the 

 European continent from a home originally insular? The 

 species (two, at least) have seemingly not yet been found in the 

 western hemisphere outside of the Bermudas, and possibly they 

 do not occur elsewhere. If this is the case it is hardly likely 

 that they could have been carried (except through the agency of 

 man) from the Bermudas to the Azores or the Canaries, since 

 the first-named islands lie considerably to the eastward of the 

 Gulf current, although still within the influence of the Gulf- 

 drift. The fact that none of the species of the peculiar genus 

 Poecilozonites are found in the Azores or the Canaries is a fur- 

 ther argument against an assumed eastwardly transport. On the 

 other hand, it is just possible that the Bermudas have received 

 these species from the Azores and Canaries through the return 

 Lusitanian and equatorial currents, and that the Azores fur- 

 nished to Europe the continental representatives of the species. 

 There would be nothing strange in this, and the northern posi- 

 tion of the return currental flow might explain the absence of 

 these forms from the West Indian Islands. That islands, which 

 are favorably situated as far as winds and currents are con- 

 cerned, should have. transmitted to continental areas portions 

 of their faunas is what we should but expect. It is not only 

 that the continents furnish the islands, but necessarily the 

 islands must furnish the continents, but to what extent this 

 reciprocal action takes place cannot well be determined. From 

 various considerations Morelet has argued that some of the 

 moUuscan forms of meridional Europe must have originated 

 in, or, at least, been derived from, the Azores. If the ocean 

 currents which now pass off" the Southeastern United States 

 trended in the o[)posite direction there can be no question that 



