10 THE NAUTILUS. 



Helicodiscus parallelus (Say). Strobilops labyrinthica (Say). 



Pyramidula cronkhitei anthonyi 

 Pilsbry. 



NOTES. 



VALVATA PISCINALIS IN CANADA. I found last autumn in 

 Homsher Bay, Toronto, inside the " sea-wall," a flourishing colony 

 of Valvuta piscinalis Miill. There was much rubbish along the 

 shore, including straw and marsh grass, such as is used abroad in 

 packing fragile articles for export ; and I have no doubt these little 

 strangers were introduced from England or Eastern Europe in some 

 such material. Another alien long however known to have be- 

 come established in the United States and at Cornwall in Ontario 

 Bythinia tentaculata L., abounds nearby, in the lagoons on the islands 

 in Toronto Bay. I may add that these quiet waters also harbor fine 

 specimens of Anodonta cataracta Say (fluviatilis Dillw.) and Ano- 

 donta grandis Say. Their occurrence in the same locality should 

 end forever the contention that one is the eastern form and the other 

 the western form of the same species. The same ecological con- 

 ditions, and the commingling in the same water of the spermatozoa 

 of both, would necessarily result in hybrids or extinction of differ- 

 ences if the two species were not naturally distinct, and each capable 

 of preventing fertilization by the other. F. R. LATCHFORD. 



SOME EUROPEAN MOLLUSCA. The receipt of a new part of 

 Taylor's beautiful monograph of the Land and Freshwater Molluaca 

 of the British Isles reminds me of an observation on Helicigona 

 arbustorum var. alpicola Fer., a small rather elevated variety of a 

 yellowish color, with one band or none, which I found on the summit 

 of the Rigi, in Switzerland. The soft parts were uniformly pale 

 reddish instead of dark, and although Taylor states that the animal 

 of this species varies independently of the shell, it seems possible 

 here the two things go together, the alpicola form being perhaps a 

 valid subspecies. At Zurich and Gersau, Switzerland, I found 

 typical arbustorum ; at the latter place also the yellowish bandless 

 form. The varieties of H. arbustorum, with additional bands, fig- 

 ured by Taylor, are very interesting, but certainly the form with an 



