COi^TRIBUTIONS TO CONCHOLOGY. 



]Vo. 4. 



Eemarks on the distribution of the Terrestrial and Fresh- 

 Water MoLLuscA, WHICH INHABIT JAMAICA. — Continued 

 from p. 48. 



Four species of Succinea inhabit Jamaica, one of wliicli is proba- 

 bly identical with a Cuban species, S. Sagra. In this genus the paucity 

 of specific characters is such, that plurality of origin may often be 

 undistinguished by well marked specific differences. Specific identity 

 in such genera is by no means indicative of unity of origin. 



Sixty-one species of Helix inhabit Jamaica. H. Cubensis is a Cu- 

 ban species, of ■which variety s is said by Dr. Pfeiffer to come from 

 Jamaica. H. turbiniformis is said by the same authority to occur 

 rarely in a province of Cuba ; it is common in certain parts of Jamai- 

 ca. H. Boothiana is also common to Cuba and Jamaica. H. angus- 

 tata is said to occur in Hayti and Jamaica. H. Bainbridgei, the heav- 

 iest species of land shells in Jamaica, which occurs in the central parts 

 of the parish cf Manchester, is said by Dr. Pfeiffer, on the authority 

 of Mr, Bainbridge, to have come from Demerara. Dr. E. E. 

 Grifiith found H. sincera in Santa Cruz. The remaining fifty- 

 five species have \iot yet been found out of Jamaica. The two 

 species of Proserpina are not known to inhabit any other island. 



Thus of the two hundred and fifty-seven species which are strictly 

 terrestial, twenty-two may have been found out of Jamaica. If it 

 should be thought that the further exploration of other islands and of 

 the mainland should add to this latter number, it is equally probable 

 that the number would be much reduced by requiring absolute cer- 

 tainty in the testimony on which Jamaica species have been refei'red 

 to other habitats. 



Only nineteen fresh-water species of Mollusca in Jamaica are known 

 to me, all of which I have collected in person. The number of gen- 

 era is remarkable. Although Planorbis has seven species, the re- 

 m^^ing twelve species belong to ten genera. 



There are no Naiads, and there are but two very rare species of 



