ESMARK : MOLLUSCA OF NORWAY. Ill 



P. muscorum van lundstromi West. Lofoten. 



Subgenus ISTHMIA Gray. 

 Isthmia minutissima Hartm. Christiania, Malmden near 



Christiania. 

 I. minutissima var. odontostoma West. Akershus, 



Fsestning, and Christiania. 



Subgenus COLUMELLA West. 

 Columella edentula Drap. Eker in Christiania Stift, and 



Bergen. 

 C. edentula var. Gredleri Cles. Tdnset in Hamar Stift; 



Tromsden, Vardd, Porsangerfjord, and South Varanger. 

 Subgenus VERTIGO Miill. 

 Vertigo gravida West. Bdrsesd near Skien. 

 V. pygmaea Drap. Not very common. In the vicinity of 



Christiania, Hof in Jarlsberg, Eker, Modum, and Ringerige; 



Bergen. 

 V. substriata Jeffr. Eker, Langesund, Brevik ; Molde in 



Throndhjem Stift. 

 V. antivertigo Drap. Not common. Christiania, Hvalderne, 



and Skien. 

 V. lilljeborgi West. Rare. Skien. 

 V. alpestris Aid. Common. Round Christiania, Modum, 



Ringerige, Jarlsberg, and Hvalderne in Christiania Stift ; 



Tdnset, Lilleelvedalen, in Hamar Stift ; Porsangerfjord 



in the Amt of Finmarken. 

 V. arctica Wallenb. (P. Hoppei). ' Gaustafjeld ' in Tele- 



marken ; Vardd, The Nordkap, Porsangerfjord ; several 



localities in South Varanger ; 660 m. high on Svendborg- 



tind in Maalselvedalen. 

 V. pusiila Mill]. More common than any of the preceding 



species. In the neighbourhood of Christiania, Eker, 



Modum, Ringerige, and Vestfjorddalen in Telemarken. 

 V. angustior Jeffr. Lindden, Malmden, and Asker in 



Christiania Stift. 



