426 WEST INDIAN MOLLUSES- SIMPSON. vol. xvii. 



tries, as well as Rumina decollata, aud many others. I liave little doubt 

 that Suhulina octona has been introduced into a number of the West 

 Indian islands in this manner, for C. B. Adams mentions that in 1849 

 it was found only in a single locality in Jamaica, in a garden near 

 Kingston,* while now one can not pick up a handful of shells anywhere 

 on the island without finding it. 



Orthalicus undatus, a Mexican species now found in south Florida, 

 Cuba, Jamaica, and some of the Windward Islands, is another case in 

 point, no doubt.t 



Fourth : — By birds. Small mollusks or their eggs may be, and no 

 doubt are, sometimes carried from one locality to another in mud 

 attached to the feet or feathers of birds. And lastly, it is possible that 

 such mollusks or their eggs might be transported moderate distances 

 by windstorms, though such migrations are probably very rare.f 



A number of eminent biologists have regarded the Antillean region 

 as an independent one, and among these are De Candolle, Schouw, 

 Martins, Berghaus, Hinds, Woodward, Baird, Griesbach, Brown, 

 Sclater, Wallace, Engler, Packard, Drude, Hartlaub, and Fischer. 

 These men studied the plants, forests, animals in general, birds, and 

 mollusks. Others, among whom are Agassiz, Heilprin, and Merriam, 

 have regarded it as a subregion of the American trojpical province, 

 and still others have united it with the tropical American region. 

 Whether the evidence of the land and fresh water mollusks of the 

 Lesser Antilles goes to i)rove it a separate province may well be 

 doubted, since it is peopled so largely with South American species 

 and genera, but I believe that the character of this fauna in the 

 Greater Antilles is very distinct from any other, and that the peculiar 

 genera and subgenera of land mollusks have been developed in the locali- 

 ties where they now preponderate. 



Bland, whose exhaustive studies of the distribution of the land shells 

 of this region are well known, and whose conclusions are considered 

 authoritative, says:§ 



* Contributions to Concliology, iii, p. 48. 



t Land and fresh- water mollusks may be often carried from one country to another 

 in the cargoes or ballast of vessels. Ampullarias are frequently imported alive into 

 Europe or North America in the crevices of mahogany logs and several African 

 Achatinas have been carried with coffee plants to Mauritius and other islands of 

 the Indian Ocean, where they flovirish as vigorously as the native suails. No doubt 

 many species are introduced on plants. It may be well to mention that it is known 

 that the young of some of the ITnionida' attach themselves bv hooks to the fius and 

 gills of fishes, where they become encysted, aud in this condition may be transported 

 long distances. 



t Small fresh-water bivalves have been found attached to the legs of flying aquatic 

 insects and they may thus be borne from one body of water to another. 



§0n the Geographical Distribution of the Genera and Species of the Land Shells 

 of the West India Islands; with a Catalogue of the Species of each Island. Ann. 

 Lye. N. Y., VII, p. 335, 1861. 



