1896.] NATURAL SCIENCES OF PHILADELPHIA. 415 



2. B. ( Tomigerus f) Eamagei Smith. 



3. B. (Bulimulus) Ridleyi Smith. 



4. Pwpa solitaria Smith. 



5. Stenogyra ( Opeas) octonoides C. B. Ads. 



6. S. (^ Opeas) siibula Pfr. 



7. S. ( Opeas) Beckiana Pfr. var. 



This fauna is of South American type. While there are some 

 Australasian forms which recall Polygyratia in their shell charac- 

 ters, their anatomy is still unknown. The nearest relatives of this 

 species appear to be the continental if. po/foc?o?ifa Orbigny, and such 

 forms as H. endodonta of Ecuador. It is curious that the Helices 

 of oceanic islands so frequently belong to groups which have the 

 throat of the shell armed with spiral lamellie, and the fact will be 

 considered later in connection with the St. Helena fauna. None has 

 yet been described from the Galapagos, yet one cannot help wonder- 

 ing if the Helix not specifically named, found by Darwin, and sup- 

 posed by Cuming and himself to be identical with a Tahitian spe- 

 cies, might not have been of this type. It is obvious that the 

 Noronha fauna is too small to admit of basing much upon its char- 

 acters, but small as it is, they are quite suggestive. The second 

 species is referred with some doubt to Tomigerus by Smith. It 

 seems to the writer that the doubt is well founded, and that the 

 curious species in question is hardly more different from B. Ridleyi 

 than B. Darwini is from B.jacobi or Simrothi. 



Bulimuhis Ridleyi is fuscous with a pale peripheral line. The 

 incremental lines are cut by slender spiral stride and the shell is umbili 

 cated. The aperture recalls that of B. Simrothi and in some respects 

 that of the fossil Bulimali of the Oligocene silex beds of Tampa, 

 Florida. It is found on trees and under stones rather widely dis- 

 tributed on the island. According to Smith " It resembles some- 

 what in form certain species of Par tula ; it faintly recalls, chiefly on 

 account of color, Bulimulus jaeobi from the Galapagos Islands." It 

 will be observed that all the forms with which it is compared are of 

 insular habitat, Florida in Oligocene times having been an island, 

 while in the Oligocene beds of the continent, of the same horizon as 

 the silex beds, no Bulimuli have been found. 



Pupa solitaria Smith, is so similar to the variable P. Wolfii Mil- 

 ler of Guayaquil (P. munita and P. clausa Eeibisch of the Galapa- 

 gos) that, bearing in mind the wide dispersion of these minute spe- 

 cies, I strongly suspect a sufficient number of specimens would 



