352 



LESSER ANTILLES 



CHAP. 



PlagioiytycJia and one Thelidomus^ while St. Croix has two sub- 

 fossil Caracolus which are now living in Porto Rico, together with 

 one Plagioiotyclia and one Thelidomus (sub-fossil). The gradual 

 disappearance of some of the characteristic greater Antillean 

 forms, and the appearance of S. American forms in the Lesser 

 Antilles, is shown by the following table: — 



(f?) In Guadeloupe we find Cyclophorus^ Ampldhulimus^ 

 Homalonyx^ and Pellicula^ which are characteristic of S. America, 

 and nearly all recur in Dominica and Martinique. These islands 

 are the metropolis of Dentellaria^ a group of Helix^ evidently 

 related to some of the forms developed in the Greater Antilles. 

 Stragglers occur as far north as St. Kitt's and Antigua, and there 

 are several on the mainland as far south as Cayenne. Traces of 

 the great Bulimus^ so characteristic of South America, occur as 

 far north as S. Lucia, where also is found a Partliena (San 

 Domingo and Porto Rico). Trinidad is markedly S. American; 

 bb species in all are known, of which 22 are peculiar, 28 are 

 common to S. America (8 of these reach no farther north along 

 the islands), and onlj^ 5 are common to the Antilles, but not to 

 S. America. The occurrence of G-imdlachia in Trinidad has 

 already been mentioned. 



The Bermudas show no very marked relationship either to 

 the N. American or to the West Indian fauna. In common 

 with the former they possess a Polygyra^ with the latter (intro- 

 duced species being excluded) one species each of Hyalosagda^ 

 Suhidina^ Vaginula^ and Helicina^ so that, on the whole, they 

 may be called West Indian. The only peculiar group is Poecilo- 

 zonites^ a rather large and depressed shell of the Hyallnia type. 



(2) The Central American Sub-region may be regarded as 



