ESMARK : MOLLUSCA OF NORWAY. 97 



quantities, for itistance, Tachea hoiiensis, Arionta arbusforum, 

 Clausilia laminata, and CI. bidetitata in the park of Jarlsberg, 

 where it is porphyre, and where in the course of a few hours 

 the Countess Wedel-Jarlsberg collected thousands, particularly 

 on Angelica sylvatica and Stac'hys sylvestris. 



Not a few species have a different distribution from our 

 neighbouring countries Sweden and Finland. With us they 

 are fjund much higher towards the north, owing no doubt to 

 the milder coast climate. 



Of naked snails we have Limax inaximus up to 66° 49", 

 whilst in Sweden and in Finland it is not found higher than 

 62° 6". I have been informed that a great black snail appears 

 on one of the islands of Lofotea 68° 6", but whether it is this 

 species or the next it is impossible as yet to decide, as my in- 

 former is no zoologist, and, therefore, does not know the two 

 different genera. Arion empiricoruni var. ater is found together 

 with the preceding at 66°49'. It is not found in Siberia. 

 Lehmannia viarginata Miill. has been found by my friend 

 Student Hoyer, in Porsangerfjord, in Finmarken, in Sweden to 

 62° — 63°, but neither in Finland nor in Siberia. A. hortensis 

 is not found in Finland, nor in Sweden up to about 63°, but will 

 most likely be found further north, as it exists in Siberia, and in 

 Norway to 69°, in Trondenaes on the Island of Hindd. Arionta 

 arbustorum, both in its chief form and as var. flavescens, is found 

 up to 70° 25'. Balea perversam Sweden and in Finland ranges 

 to 60° — 61°, but with us to 67° 50" 



Freshwater moUusks also differ somewhat in distribution. 

 Pianorbis glaber Jeff, seems to thrive excellently on the little 

 island of Gaaso in Vestfjorden (68°). Of the Pisidies we find 

 Pisidiuni globulare, P. pulcheUuniy P. fossarinum^ P. obtusale, 

 P. pallidum, P. nitidu7n, and P. Scholtzii u\) to 69" — 70°, With 

 Sph(zi-ium corneum, the inverted rule seems to exist, for in 

 Sweden it is found to Lulea Lapmark (67°), but in Norway 

 only in the southern parts. On the other hand Sph. mamillaniim 

 is much more common in Norway, and goes farther towards the 

 north. 



G 



