108 BRITISH MOLLUSK9. 



Europe, where the species are most abundant and the shells larger 

 and more opake. The British species have light transparent horny- 

 shells. P. secale, the largest, is found nearly throughout England, 

 but chiefly among the chalky districts of the south and west parts. 

 It does not inhabit Scotland, nor is it found on the Continent north 

 of Grermany. The aperture of P. secale is, contracted by not fewer 

 than seven internal parietal teeth. Our most common species are 

 two of much smaller dimensions, without internal parietal teeth, 

 P. muscorum and cylindracea. The first ranges on the Continent 

 from Lapland to Sicily, the second has a rather more southern 

 range, extending to Algeria. Both inhabit the British Islands 

 throughout, P. cylindracea being the commoner of the two. The 

 remaining species, P. Anglica, — with two or more internal teeth, the 

 smallest of the genus, but larger than any Vertigo, — is more scarce. 

 Abroad it has only been observed in Portugal and the south of 

 France, and in Algeria. 



The Pupce are chiefly members of the great Caucasian province 

 of the Eastern Hemisphere. After eHminating about seventy from 

 the described list as belonging to Vertigo, about one hundred and 

 fifty remain, nearly half of which are South European. Of the 

 remaining seventy-five, rather more than half are distributed in 

 other parts of the Eastern Hemisphere, as follows : — Madeira, four- 

 teen ; Mauritius and Madagascar, twelve ; South Africa, five ; 

 West Africa and Canary Islands, five ; India, four ; Ceylon, two ; 

 Australia, one ; New Zealand, one. The remainder belonging to 

 the Western Hemisphere, range as follows : — West Indies, the next 

 principal station to Europe, thirty ; South United States, three ; 

 Bolivia, two. 



The British species are :— 



1. secale. Shell rather large, elongately cylindrical, of from 



eight to nine densely ridge-striated whorls ; aperture seven- 

 toothed. 



2. muscorum. Shell small, oblong-cylindrical, of from six to 



seven glossy semitransparent whorls ; aperture sometimes 

 toothless, sometimes one-toothed. 



3. cylindracea. Shell very small, shortly cylindrical, of six trans- 



parent rather swollen whorls ; aperture one-toothed. 



4. Anglica. Shell rather minute, of six semitransparent some- 



what narrow whorls ; aperture subtriangular live-toothed. 



