1893.] NATURAL SCIENCES OF PHILADELPHIA. 257 



" Yallonia adela West., Ystad ; ex auctore," kindly forwarded by 

 Mr. Pilsbry, are evidently incorrectly named. One of them is V. 

 pulehella with rather elevated spire, and a well-formed lip ; the other 

 costata with (for the species) also an elevated spire and strongly 

 descending last whorl. 



The species has not been figured. 



3a. V. declivis (?) n. sp. Man. Conch., PI. 32, fig. 10-13. 



Shell of medium size, depressed conic, widely and regularly 

 umbilicated, whitish, transparent, surface with fine, dense stride, 

 nucleus smooth ; whorls 4, gradually increasing, with a rather deep 

 suture, the last well-rounded, not predominating, slightly expanding 

 toward the aperture and gradually descending in its last third to the 

 periphery of the penultimate whorl or rather below it ; aperture 

 moderately inclined and oblique, nearly t crescentic-circular, the 

 inferior end of margin slightly protracted ; peristome straight 

 above, and very narrowly everted at the periphery and the inferior 

 part, with a thin but distinct lip. 



Diam. maj. 2"6, min. 2*4, alt. 1*4 mm. 



Soft parts not seen. 



Distribution : Central Europe. I received, about 12 years ago, 

 from Mr. S. Clessin, as Hel. tenuilabris Braun, 3 examples from the 

 drift on the Danube River, in Bavaria. Although dead shells, 

 they are fresh and well-preserved, and all exactly alike. I found 

 another specimen in drift on the Aar River, in Switzerland, also in 

 good condition, and of the same size and shape as those from the 

 Danube, except that it has no lip, and the margin is simple and 

 straight ; it may not, however, be mature. 



This form is evidently not V. tenuilabris of A. Braun, as it does 

 not correspond' at all in several different points, with the description 

 of that species, nor any other known to me. It would, consequently, 

 not be amiss to propose a specific name for it. 



It is not " densely and acutely, finely ribbed," but very finely 

 striate, apj^earing almost smooth and shining ; the peristome is not 

 everted, or very narrowly and indistinctly so, while in tenuilabris it is 

 " widened " (which evidently means everted) and the inferior margin 

 reflexed ; the aperture is not " transversely oval-rounded," and not 

 "very oblique," and the margins are not " very approximate," but, 

 for a Yallonia, markedly distant; the shell is not "grayish-horn 

 with peristome yellowish horn colored," but whitish transparent 

 throughout. 



