258 PROCEEDINGS OF THE ACADEMY OF [1893. 



It differs from V. pulchella in its somewhat larger size, the 

 wider and more regular umbilicus, the whorls being \ more in num- 

 ber and more slowly increasing, the last comparatively narrower, 

 gradually descending entirely to the aperture, and the peristome 

 being straight or just perceptibly everted with a much thinner lip. 



V. declivis var. altilis, nov. Man. Conch., PI. 32, fig. 14-17. 



This form differs from the above in its somewhat larger size, nar- 

 rower and deeper umbilicus, more elevated spire, the last whorl 

 descending below the circumference of the penultimate; the peris- 

 tome being quite straight and thin, without a lip ; the aperture is 

 very little oblique, in fact, the least so of all the Vallonia I know, 

 and moderately inclined, rather higher than wide, subangular 

 inward at the base; whorls 4i ; the color is whitish, the surface 

 densely, rather regularly striate. 



Diam. maj. 29 min. 2*5, alt. 1*7 mm. 



This form might represent a species, but, from its similarity to 

 declivis, and the few examples known, I prefer, for the present, to 

 regard it as a variety. 



I found one specimen in 1882, also in drift on the Aar River, 

 Switzerland. Another has been kindly forwarded by Mr. Pilsbry, 

 it is from drift on the Main River, in Middle Germany, and bears 

 also the name H. tenuilabris Braun. They are exactly alike. 



I found, in 1882, while in Switzerland, among drift shells from 

 the Doubs River, on the western slope of the Jura Mountains, a few 

 specimens of either declivis or altilis, having then labeled them also 

 H. tenuilabris A. Br. 



All the examples of this species extant, though dead shells and 

 found in drift, are fresh and in good condition, and it is to be 

 expected that living specimens will be found in those countries. If 

 a new species has been established on the few specimens, it is 

 because they could not reasonably be brought under one of those 

 already known without modifying their diagnoses so that they would 

 have been valueless. 



I believed for a time that this might be the V. adela of Wester- 

 lund, judging from the description. Butthe author says expressly that 

 the last whorl does not descend at all, 23 while in the forms under 

 consideration this is just the prominent feature. Since I failed to 



23 Conf. Westerlund Fauna, I Suppl. 1890, p. 120, H. tenuilabris var. under V. 

 mionecton Bttg., also cited below, No. 1-1. 



