20 Geographwal Distribution 



more than one island are enumerated as belonging to eacli; 

 but the number peculiar to the islands exceeds one thousand. 



The foregoing remarks are with regard to the relationship of 

 the West India Islands generally with the American continents, 

 and the division of the islands into two groups, those west and 

 those east and south of Portorico, which itself rather belongs to 

 the latter, but this gives an inadequate idea of the interesting 

 and peculiar character of these Insular ftiunas. My limits pre- 

 clude any very extended observations ; but I propose to state 

 some, at least, of the most striking facts as to the relationships 

 of the islands inter se. 



The Bahamas, Cuba, and the Isle of Pines are especially con- 

 nected ; Cuba has 17 species found also in Jamaica, 8 in Haiti, 

 15 in Portorico, and 13 in the islands east and south of Porto- 

 rico. The development of the subgenus Strophia (Pupa), of 

 Macroceramus, Megalomastoma, Ctenopoma, Chondropoma, 

 Trochatella, and Ilelicina, the occurrence of the only Balea, 

 and the absence of Geomelania,* Jamaicia, Licina, Stoastoma, 

 and Lucidella are the principal peculiarities of the Cuban 

 fauna. With respect to Jamaica, there are common to it and 

 to Cuba IT, to Haiti 4, to Portorico 10, and to the islands east 

 and south of that island 10 species. The numerous represen- 

 tatives of Sagda (Helix), Proserpina, Adamsiella, Cyclostomus, 

 Tudora, and Alcadia, the exclusive presence of Geomelania, 

 Jamaicia, Licina, Stoastoma (witli the exception of one species 

 in Portorico and one in Opara), and Lucidella, and the absence 

 of Strophia (Pupa), Megalomastoma, and Chondropoma, greatly 

 distinguish Jamaica from the neighboring islands. I doubt 

 whether any province in the world of equal area is so rich as 

 Jamaica both in genera and species. Haiti has in common 

 with Cuba 8, with Jamaica 4, with Portorico 8, and with the 

 islands east and south of the latter 8 species. This island has 

 the following peculiarities — the development of Macroceramus 



* Information received at a late moment induces me to suspect the occurrence 

 of Geomelania in Cuba. 



