1893.] NATURAL SCIENCES OF PHILADELPHIA. 267 



tour vers l'ouverture, le characttre de son ombilic qui est aussi un 

 peu plus grand; la croissance plus rapide des tours qui sont un peu 

 moius nombreux, enfin par sa taille plus faible." The size is not 

 given. 



This description would fairly well correspond with V. parvula, 

 but for one point. Ancey says: "son ouverture a bords distant," 

 while in our species they are much approximate, even more so than 

 in costata and in cyclophorella. We can hardly understand how 

 Ancey would characterize V. americana by comparing it with cyclo- 

 phorella if it were the present species, since the two are very differ- 

 ent. There is no description of the color or the structure of the 

 surface. I did not succeed in procuring specimens for comparison. 



There is a note in Mr. Cockerell's letter worth communicating : 

 " costata var. minor — very small, diam. l^-lf mm., compact, aper- 

 ture round, ribs very prominent." This small form, which may, 

 perhaps, fall as a subvariety under americana, was found by Mr. D. 

 B. Cockerell at Niagara Falls, on the Canadian side. When send- 

 ing it to me he remarked: "The only place I found this variety 

 was on the Canadian side, although the type was common every- 

 where else but where I found var. costata." I confess that the mean- 

 ing of the last sentence is somewhat obscure to me. But the fact is 

 stated of the existence of a small costate form in that locality. Any 

 conchologists visiting Niagara Falls should be on the lookout for 

 this Vallonia, as well as for others. Mr. Cockerell wrote me that 

 the specimens in question had been accidentally destroyed. 



8. V. tenera Reinhard. 



Hel. tenera Reinhard, Jahrb. D. Mai. Ges., 1877, p. 322, T. XI, f. 4. 

 (?) Hel. pulchellula Heude, Moll. Terr. Fl. Bleu, 1882. p. 20, T. 8. f. 17. 27 

 (?) Hel. pulchellula Hilber, Sitzungsber. K. Acad. Wiss. Wien, LXXXVI, p. 

 3. aT 



(?) Hel. pulchellula O. v. Moellendorff, Jahrb. D. Mai. Ges., 1884, p. 315. 



Unfortunately, the original descriptions are not accessible to me. 

 From two authentic specimens in the collection of the Academy, 

 fresh and evidently mature, or nearly so, we can characterize V. 

 tenera as follows : 



Shell rather small and of the general appearance of V. costata, 

 with spire little elevated, very depressed, conic, light grayish horn 

 colored, thin and transparent, somewhat shining; surface with 

 rather fine and dense membranous ribs, about 33-43 on the last 

 whorl ; umbilicus rather wide and regular, a little more widened for 



27 Cited from Mcellertdorff, /. c. 



