XI 



CUBA — JAMAICA 



347 



sist mainly of Helicina proper (58 sp.), which here attains by 

 far its finest development in point of size and beauty, and 

 of Eutrochatella (21 sp.), which is peculiar to the three great 

 islands (Jamaica 6 sp., San Domingo 6 sp.). 



The Bahamas^ consisting in all of more than 700 islands, are 

 very imperfectly known, but appear to be related partly to Cuba, 

 partly to San Domingo, from each of which they are separated 

 by a narrow channel of very deep water. They are certainly 

 not rich in the characteristic groups of the Greater Antilles. 

 The principal forms of Helix are Plagioptycha (6 sp.), common 

 with San Domingo, and Hemitrochus (6 sp.), common with Cuba. 



Fig. 229. — Characteristic 

 Cuban Helices. A, 

 Polydontes imperator 

 Montf. B, Caracolus 

 rostrata Pfr. C, Poly- 

 tnita muscarum Lea. 



Strophia is exceedingly abundant, but Cylindrella^ Macroceramus^ 

 and G-landina have but few species. There are a few species of 

 Ctenopoma^ Cliondropoma^ and Cistxla^ while a single Schasieheila 

 (absent from the rest of the sub-region) forms a link with 

 Mexico. 



Southern Florida^ with one or two species each of Hemitrochus^ 

 Cylindrella^ Macroceramus^ Strop)hia^ Ctenopoma, and Chondro- 

 poma^ belongs to this province. 



(5) Jamaica. — The land Mollusca of Jamaica are, in point of 

 numbers and variety, quite unequalled in the world. There are 

 in all as many as 56 genera and more than 4-40 species, the 

 latter being nearly all peculiar. The principal features are the 



