1893.] NATURAL SCIENCES OF PHILADELPHIA. 249 



Our species has a wide geographical distribution. It is found all 

 over Europe, in Northern Africa, 15 the Azores and Madeira, in at 

 least Western and Northern Asia, and the greater part of North 

 America. It seems to be absent or scarce in Eastern Asia, as well 

 as on the Pacific slope of North America, and considering the rela- 

 tions of those faunas, this coincidence would not be surprising. 

 From California, I have seen only specimens taken in a green-house 

 at San Jose, and they may have been introduced there with plants. 

 I can not remember having found a report of them from the Pacific 

 coast, although Vallonia has been found on the Sierra Nevada. It 

 has not been reported from some of the Gulf States. It has been 

 reported from Florida, but Dall, in his paper on Florida land and 

 fresh water mollusca, does not enumerate it. I have received 

 several specimens lately from Mauritius, labeled as an unknown 

 Helix. There are specimens from New South Wales, Australia, 

 in the National Museum. As already said, they are probably 

 introduced from Europe. 



It must be borne in mind that many faunal reports, especially 

 the older ones, should be received with reserve, since several species 

 have been included under this name, which for a long time repre- 

 sented the entire genus. In collections, two or more different spe- 

 cies are generally confounded. In our country the name pulchella 

 was partly replaced by (Helix) minuta Say, the validity of which 

 name will be found discussed under V. excentrica. 



Our species has also been found fossil in the loess, etc., over a 

 great part of both continents, often associated with V. costata, tenui- 

 labris and probably other species. 



It may be mentioned that about eighteen specimens from Pitts- 

 burgh, Pa., in the Academy's collection, are all darkened with a 

 distinctly sooty coat, an effect of civilization upon snails ! 



V. pulchella is variable in size. While the average size is 2*4 mm. 

 or rather less, the smallest specimens measure 2*0, the largest 2*7, 

 but either extreme is exceptional, and I have seen none of 3 mm. 16 



15 Dr. W. Kobelt, in the report on his collecting trips in Tunis, Algeria and 

 Morocco [Excursionen in Nordafrica, Nachrichtsbl. d. D. Mai. Ges. ( 1884-86, 

 Eine Excursion nach Nord-Marocco, ibid. 1881, p. 149] does not mention this or 

 any other species of Vallonia. They seem, consequently, to be at least scarce 

 there. 



16 The following are measurements of specimens from different localities : 



Average. Largest. Smallest. 



Hermannstadt, Transylvania., 2'3 2'3 2'2 



Montecchio, Italy 23 2'5 2-1 



Sicily 2-3 24 22 



17 



