OP CONCHOLOOY. 365 



oped in Africa, has a single species (P. bicolor, Gould), proba- 

 bly introduced from the East Indies where it is widely dis- 

 tributed, in St. Thomas, and in Trinidad embraced in the 

 Guadeloupe subprovince. 



Several subfossil species are found in St. Croix, and among 

 them H caracolla and H marginella, Gmel., — also two species 

 of Strophia, none of which are now living on the Island. Im- 

 pressions of an undetermined species of Strophia occur also 

 in the fossil guano of Sombrero.* 



The fauna of the Porto Rico subprovince has closer relations 

 with that of Haiti, than of Jamaica or Cuba. 



5. Guadeloupe and Martinique, with Bar' uda and the Islands 

 between it and them, and also Islands to the South, to and inclu- 

 sive of Trinidad. There is, as before observed, a very marked 

 decline in this subprovince of genera especially characteristic 

 of the West Indian fauna. Of Helix, the subgenus Thelido- 

 mus, belonging to Cuba and Jamaica, and Cepolis of Haiti, are 

 represented in Martinique, the former by H. discolor, Fer., and 

 the latter by H. auridens, Rang. Morchia, (subgenus of Hya- 

 lind) has H. Baudoni, Pet. (closely allied to H. concolor, Fer., 

 of Porto Rico) in Guadeloupe. 



With very few exceptions, the rest of the Helices in this 

 subprovince belong to the subgenus Dentellaria. That subge- 

 nus is represented in most of the Islands, and is, indeed, the 

 characteristic form of this subprovince, but it is not found in 

 St. Vincent or Trinidad. 



Albers places H. lychnnchus, Mull., (erroneously attributing 

 it to Porto Rico) in Dentellaria ; but St. Simon (Jour, de 

 Conch., 1853), with reference to some anatomical peculiarity 

 and the form of the buccal plate, refers it to Zonites. He sug- 

 gests that H. acuta, Lam., the shell of which is somewhat anal- 

 agous to that of lychnuchus, may have a similar organization, 

 and also belong to Zonites, — the buccal plate of the former is, 

 however, strongly ribbed, and has marginal denticles. 



It is remarkable that Thelidomus discolor and the following 

 species of Dentellaria, as well as various species of other gen- 

 era, found in the Guadeloupe subprovince, also inhabit French 

 Guiana, viz : orbiculata, Isabella, dentiens, nux denticulata, and 

 badi.a. 



Dorcasia (Helix) similaris, Fer., found in South America 

 and other parts of the world, also occurs in Barbados. 



The existence of Stenopus (8. lividus, Guild., and S. cruen- 

 tus, Guild.) in the Island of St. Vincent is a very marked 

 feature of the fauna of the Guadeloupe subprovince. This 

 genus is allied to Nanina (an Asiatic form), in which the 



* A very interesting paper on the Geology of the Key of Sombrero, 

 by Alexis A. Julien, will be found in the Ann. of the Lyceum, VIII., 18G6. 



