MOLLTJSCA OF LOWER CANADA. 51 



the land and fresh-water shells of the district in question. Eleven 

 of our Lower Canadian species occur also west of the Rocky Moun- 

 tains. These are, 



Margaritana margaritifera, Linn. Limnsea stagnalis, Linn. 

 Valvata sincera, Say. " palustris, Mull. 



Physa heterostropha, Say. " catascopium, Say. 



" hypnorum, Linn. " solida, Lea. 



Planorbis corpulentus, Say. (= L. apicina, Lea.) 



" trivolvis, Say. " pallida, Adams. 



According to Mr. Binney, the Planorbis glabratus of Say also 

 inhabits both the Pacific and Atlantic sides of these mountains, 

 but as yet this species has not been detected in Lower Canada. 

 Again, in this Province we have several species, partly land and 

 partly fresh-water, which also inhabit the continent of Europe. 

 Some of these shells, however, present slight differences, and have 

 been considered distinct species. Thus the following unquestion- 

 ably inhabit both sides of the Atlantic, 



Helix hortensis, Muller. Physa hypnorum, Linn. 



" rufescens, Pennant. (= P. elongata, Say.) 



" pulchella, Muller. Limnsea stagnalis, Linn. 



Balimus lubricus, Mull. (= L. jugularis, Say.) 



Margaritana margaritifera, Linn. " palustris, Linn. 



(=L. 'elodes, Say.) 



The following European and Canadian species may prove 

 identical : 



Lower Canada. JZurope. 



Limax campestris, Gould. — Limax agrestis, Muller. 



Vitrina limpida, Gould. = Vitrina pellucida, Muller. 



Succinea obliqua, Say. = Succinea amphibia, Linn. 



" ovalis, Say. = " Pfeifferi, Rossmass. 



Helix chersina, Say. = Helix fulva, Muller. 



Physa heterostropha, Say. = Physa fontinalis, Linn. 



Pisidium Virginicum, Brongn. = Pisidium amnicum, Muller. 



Anodonta cataracta, Say. -= Anodonta cygnea, Linn. 



It may be observed that a much larger percentage of the ma- 

 rine shells of the Gulf of the St. Lawrence also inhabit Great Bri- 

 tain and Northern Europe. Dead shells of the European Helix 

 cellaria have been found by Mr. Fowler near gardens in Craig 

 Street, Montreal. Helix rufescens, probably has also been intro- 

 duced from Europe, and possibly Helix hortensis. The remainder 

 would appear to be of exclusively North American origin, and 

 confined to the region east of the Rocky Mountain?. 



