[86] 



province, compared witTi the preceding, has fewer peculiar 

 forms of Helix. Caracolus is represented bj H. caracolla, L., 

 and a. marginella, Gmel.; the former found also in Haiti, the 

 latter of the same type as H. Sagemon, Beck, of Cuba. Eury- 

 cratera [H. angulata, Fer.) and Plagioi^tycha [H. Riisei, Pfr.) are 

 represented in Porto Rico and Yieque, and the last by H. ne- 

 moralina, Pet., in the Virgin Islands. Thelidomus, especially 

 Cuban, has in this subprovince, according to Albers, several 

 species, of which H. limo., Fer., is the type, but he has H, cas- 

 trensis^ Pfr., its very near ally, in Dentellaria^ to which it 

 scarcely belongs. Morchia, subgenus of Hyalina^ is repre- 

 sented in Porto Rico by H. concolor, Fer. 



Strophia has P. raicrostoma, Pfr., and P. striatella, Fer., in 

 Porto Rico, and the latter, I believe, also in Anegada, — both 

 are found in Plaiti. 



Stenogyra has Oheliscus terebraster, Lam., and Pseudohalea 

 hasta, Plr. in Porto Rico, and Melaniella gracillima^ Pfr., (found 

 also in Cuba and Florida) in St. Thomas. 



Macroceramiis has two species, M. microclon, Pfr., in Porto 

 Rico, St. Thomas, St. John and Tortola, M. signatus, Guild, 

 in the latter Island and Anguilla. Anoma and Zm are absent. 



In this subprovince there are no strictly North American 

 forms. 



Oleacina (G. glabra, Pfr.) and Varicella [G. terehrseformis^ 

 Shuttl.) are represented in Porto Rico alone, and by few spe- 

 cies. Spiraxis does not occur. Cylindrella has a small num- 

 ber of species, chiefly of the subgenus Mychostoma, one of 

 which, C. pallida, Guild., is widely distributed. 



There is in this subprovince, as compared especially with 

 Cuba ai.d Jamaica, a marked diminution of Mexican and 

 Central American forms. It may, in fact, be said that east- 

 ward from Cuba to the eastern limit of the Porto Rico sub- 

 province, those, as well as strictly West Indian forms, dimin- 

 ish gradually in number, being at their minimum in the 

 Guadeloupe subprovince. 



Orthalicus does not occur, but more subgenera of Bull- 

 mulus are represented than in the Islands to the westward. 

 Besides Mesemhrinus {B. elo7igaius, Bolt.), TJwMwastus {B. 

 exilis, Gmel ), Leptomerus (B fraterculus, Fer.), and Liostracusf 

 (B. Hjalmarsoni, Pfr.), Drymaeus has B. liliaceus, Fer. 



Leptinaria {G. Antillarum, Shuttl.) has three species, and 

 Simpulopsis one, as already mentioned. 



The only West Indian species of Clausilia, C. tridens, Schweig., 

 of the subgenus Nenia, inhabits Porto Rico. The genus is 

 not represented on the Northern, but there are several species 

 on the Southern Continent. 



Ennea (subgenus of Pupa\ which is more especially devel- 



