202 LAND RJiGIONS. 



genus Schasicheila has a single species, and is nowhere else 

 represented in the West Indies. The Caribbsean group Strophia 

 of Pupa has 8 species. 



2. Cuba and Isle of Pines. More than 600 species have been 

 described, of which 250 species are operculates. These are all, 

 with the trifling exception of 53, confined to the island; all the 

 operculates except the Truncatellas are thus restricted. The 

 dominant genera are : Strophia (19 out of 36 known species), 

 Macroceramus (31 out of 51), Gylindrella (93 out of 140), 

 Megalomastoma (12 out of 29 >, Chondropoma (51 out of 100), 

 Cistula (15 out of 42), Ctenopoma (23 out of 26). There are 

 also lY species of Glandina, 16 of Helix (largely of special 

 groups,) 30 of Stenogyridse, 10 of Suceinea, 78 of Helicinidse, 

 etc. Fresh-water shells, as in the other islands, are scarce ; 

 there are 39 gastropods, 6 lamellibranchiates, including the only 

 two species of Unio in the West Indies. 



3. Jamaica. This island is almost as rich in mollusks as 

 Cuba, containing 500 species, nearly half of which are operculates. 

 The genera Greomelania, Chittya and Jamaicia are peculiar to 

 the island, and Stoastoma and Lucidella each have only a single 

 extra-limital species. The other characteristic mollusks are : 

 Adamsiella (12 out of 17 known species), Tudora (17 out of 33), 

 Helices, nearly 100 species (including the groups Sagda, Pleuro- 

 donta, Caracolla, Dentellaria), the groups Lia and Casta of 

 Cylindrella, numerous Cyclotus, etc. The genera Strophia 

 (Pupa), Licina and Magalomastoma found in Cuba are not here 

 represented. Only 41 Jamaica species occur in other localities. 



4. Haiti and A^avassa. Haiti has about 200 species, of which 

 70 are operculated, and 2 (Planorbis) fluviatile. The island has 

 not been so thoroughly explored for mollusks as either Cuba or 

 Jamaica, and will probably yield much richer results than those 

 already recorded. There are no restricted genera, but those 

 most largely developed are : Grlandina, etc., 10, Helix 43, Macro- 

 ceramus 10, Cylindrella 30, Stenogyra 12, Choanopoma 12, 

 Helicinidse 29. There is a single species of the Jamaica group 

 Lia. 



The guano island of Navassa has so far furnished only three 

 species, all peculiar. 



5. Po7'to Rico, and neighboring Islands. About 120 species are 

 recorded ; among them the genus Gseotis is restricted to Porto 

 Rico, where lives also the only West Indian Clau^ilia, of the 

 group Nenia. The operculates are less developed in this island 

 than elsewhere, the genera Tudora, Cyclostoma, Ctenopoma, 

 Greomelania, Jamaicia, Adamsiella, Lucidella, Diplopoma and 

 Trochatella being absent. 



6. Guadeloupe, Martinique and neighboring Islands. The 

 characteristic group is Dentellaria (Helix), several species of 



