GENERAL DISCUSSION 



TABLE II. DISTRIBUTION OF AMERICAN LAND SHELLS 



NORTH OF LATITUDE 49°. — Continued. 



Name of Specie 



Pristiloma taylori 



Pristiloma? arctica 



Agriolimax agrestis 



Agriolimax hyperboreus... 



Agriolimax berendti 



Prophysaon andersoni 



Prophysaon var. pallidum 

 Prophysaon var. pacificum 



Prophysaon humile 



Ariolimax columbianus 



Pyramidula solitaria 



Pyraniidula striatella 



Pyramidula cronkhitei 



Pyramidula asteriscus 



Oreohelix strigosa 



Oreohelix var. cooperi 



Helicodiscus lineatus 



Punctum pygra:eum 



Punctum clappi 



Punctum conspectum 



Sphyradium edentulum 



Succinea oregonensis 



Succinea retusa 



Succinea hawkinsi 



Succinea avara 



Succinea gronlandica 



Succinea grosvenori 



Succinea var. alaskana 



Succinea rusticana 



Succinea nuttalliana 



Succinea obliqua 



Succinea chrysis 



Siphonaria thersites 



Onchidium boreale 



Carychium exiguum 



Carychium exile 



(?) 



(?) 



.49O00' 

 71 25 

 61 00 

 65 00 

 49 00 

 49 00 



54 45 

 49 00 



55 38 

 58 00 

 52 00 

 61 00 



61 00 

 49 00 



49 30 



49 00 



50 00 

 50 00 



49 00 



60 00 

 65 20 

 49 00 

 67 00 

 57 00 



62 00 

 65 00 



62 00 



63 30 

 49 00 



49 00 



61 00 



65 30 

 60 30 

 60 30 



50 00 

 50 00 



III. SUMMARY OF THE MOLLUSK FAUNA OF NORTHEAST- 

 ERN ASIA. 



The land shell fauna of the northeast extremity of Asia has 

 little individualit}'-, but represents a mingling of the depauper- 

 ated extremes of the faunas of northeast China, and of Europe, 

 with that series of species which is sometimes called the circum- 

 polar or circumboreal fauna. 



