100 THE NAUTILUS. 



SOME NOTES ON NORTH AMEEICAN FORMS OF VALLONIA. 



BY DR. V. 8TERKI. 



According to the investigations of Dr. v. Ihering' this group 

 is to be separated from Helix and regarded as a genus, for anatom- 

 ical characters. The study of these forms seems to have been some- 

 what neglected in our country. These are some distinct and char- 

 acteristic forms and probably more will be found. Those known to 

 me at present are shortly pointed out in the following, in order to 

 direct the attention of conchologists to them and have them col- 

 lected wherever and whenever possible, with records of the natural 

 features of their habits. 



1. V. pulchella ^Miiller, the common form of the old and new 

 continents. Here it seems to be remarkably constant in its appear- 

 ance throughout the country, while on the other handj slightly but 

 constantly different forms may be found in neighboring places. 

 Besides the smooth surface it is characterized by the slowly increas- 

 ing whorls, the inner ones being comparatively large, and the last 

 not so peripheric as in most of the other forms. 



2. V. costata Miiller. The typical form seems to be not gener- 

 ally distributed, in North America. It deserves specific rank, be- 

 side pulchella, and differs from the latter not merely by the rib-strise^ 

 but by the more depressed spire, the more rapidly increasing whorls, 

 the last one being more peripheral, so that a costata may be recog- 

 nized, even Avhen the ribs are wanting ; generally it is also some- 

 what smaller ; thus I found them in Europe as well as in this coun- 

 try. And the fact that the two forms keep distinct side by side, on 

 both continents, is in itself a strong e\adence in favor of their being 

 different species. In some localities the one is found predominant^ 

 or exclusively, in some the other, and -frequently they are found 

 together. 



3. From Illinois (Mr. Jas. H. Ferriss), Iowa (Prof. B. Shimek 

 and Mr. Geo. W. Webster) and Kansas (Mr. Frank J. Ford) I have, 

 in 1890 and '91, obtained a peculiar form : it is decidedly smaller 

 (in bulk about 2 of pulchella), strongly costate, the umbilicus com- 

 paratively wider than in costata, especially widening towards the 

 aperture by the last whorl receding to the periphery, so that the 



1 Les Relations Naturelles des Cochlides et des Ichnopodes, Bull. Scient. 

 1891, p. 214. 



