OF CONCHOLOGY. 27 



Bulimus to Achatina, &c. The discrepancy between the fauna 

 of the two continents is greatest in the south, and the concord- 

 ance greatest in the arctic region, being inhabited by the same 

 genera, with probably identical species. 



The land shells of Greenland are nearly allied to those of Ice- 

 land. The Vitrina, the Suecinea, Hyalina alliaria, accord 

 better with the species of Iceland than with American species. 

 The fresh-water species of Greenland, however, are entirely dif- 

 ferent from those of Iceland. The Limncea of Iceland belong to 

 Radix, while those of Greenland all belong to Limnophysa, — 

 both genera common to Europe and America. The Planorbis of 

 Greenland is perhaps PL p>arvus, Say, of America, or Planorbis 

 spirorbis, Rm., f. 63 (PL Dazuri, nob.) Pisidium Steenbuchii 

 of Greenland is most allied to P. pulchellum, found in Iceland 

 and Europe, but is much larger. Although the arctic species 

 are small, they are the largest in the group of species to which 

 they belong. Thus Suecinea Grroenlandica is larger than S. 

 arenaria ; Vitrina larger than any European species, except 

 perhaps Vitrina major ; the Pupa is the largest of the Vertigos. 



The following species are those whose identity is litigated : 



AMERICA. GREENLAND. ICELAND. EUROPE. 



Vitrina Umpida, Gould. V. angelica. V. angelica, t V. beryllina, Pfr. 



Hyalina arborea, Say. H. Iiammonis, Stein. H. Iiammonis. 



Hyalina electrina, Gould. 



Hyalina glapkyra. Say. H. alliaria. H.ulliaria. H. alliaria. 



(hunt us chersina, Say. G. Fabricii, B. H.fulva et Merloni. 



Zoogenetes karpa, Say. ■£ harpa et Z. amurentis, 



Gerstf. 



Vallrmia minuta, Say. V- pulchella, Mull. 



Suecinea. sp. S. groenland ica. S. groenlandica. S. arenaria. 



Pisidium sp. P. Steenbuchii. P. pulchellum. P. pulehellum. 



Margaritina margaritifera. M- mai garitifera. 



It looks very probable, from the researches of Mr. Morse, 

 that Vallonia pulchella and V. minuta ; Hyalina electrina and 

 H. hammonis (radiatula), are different species. The relation be- 

 tween the species of Comdus, Vitrina and Suecinea is still very 

 doubtful to me. Zoogenetes harpa, Say, is found abundantly in 

 Lapland, Finmarck, Temtland, and Hougheim, in Norway. It 

 is probably H. amurensis, Gerstfeld, p. 13, fig. 26. Helicogena 

 hortensis, Mull., is probably introduced in Newfoundland. 



I have sent specimens of such Greenland species as I can spare 

 to the most important American conchological institutions and 

 conchologists. 



PULMONATA GEOPHILA, Fer. 

 1. Vitrina Angelica, Beck. Plate 3, fig. 1, 4. 



T. vitrea convexiuscula lutea-virente, polita ; anfractibus 3^, 

 utrinque fere sequaliter elevatis ; apertura mediocri rotundata 



