374 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



this expansion of the last whorl makes the shell slightly iinsymmet- 

 rical. Peristome thin and acute, without callue, thickenings or 

 indentations in the palatal wall. Lines of growth weak and oblique ; 

 apex smooth. Aperture larger in proportion to the shell than in 

 either S. hasta or 8. edentulum; entirely without teeth or lamellae. 

 The umbilicus is very slightly perforate. 



Height. Diameter. 

 3. 33 1. 74 



2.81 1. 11 ^ 



2. 70 1. 14 



This species is found at various places as a fossil in the Pleistocene 

 and Loess deposits of the Mississippi Valley.^ It is also found in 

 several States of the Rocky Mountain region at the present time; 

 i. e., in Utah, Colorado, and Wyoming. 



Its abundance in the Pleistocene beds of Long Island, Phillips 

 County, Kansas, shows that at one time this was a very common 

 shell. Many specimens were found there in 1910 by ^Mr. Johnston 

 and the writer. They were associated with S. Tiasta and other Pupil- 

 lidae which are at the present time apparently extinct. 



This species can not be confused with any other United States land 

 mollusk. The much greater height of the shell and the greater num- 

 ber of whorls shows it at once to be distinct from aS'. edentulum. 



SPHYRADIUM EDENTULUM Drapamaud. 



Pupa edentula Draparnaud, Hist. Moll., 1805, jj. 52, pi. 3, figs. 28, 29. 



Pupa simplex Gould, Bost. Journ. Nat. Hist., vol. 3, 1840, p. 403, pi. 3, fig. 21. 



Vertigo simplex (Gould) Binney, Man. Amer. Land Shells, 1885, p. 191, fig 195. 



Shell, smaller than either of the two preceding species, not more 

 than 2 mm. in height; translucent brown in color, the apex not 

 lighter than the body of the shell in live specimens. Outline conical 

 rather than cylindrical; apex obtuse. Wliorls four to five, well 

 rounded on the face and wnth the sutures well impressed. Lines of 

 growth very faint and oblique. Shell not spoiled in symmetry by the 

 last whorl increasing in size unproportionately . Aperture well rounded 

 and proportionately not so large as in S. alticolum; entirely without 

 teeth or lamellae. Peristome thin and acute, without callous thick- 

 enings or indentations. Umbilicus minutely perforate. 



Height, 1.60 mm.; diameter, O.SO mm. 



The shell does not vary appreciably in size. It is a resident in that 

 part of North America designated by the United States Biological 

 Survey ^ as Transition and Canadian. It is also a resident of the 

 northern parts of Europe and Asia. 



1 Pilsbry, Nautilus, vol. 11, 1898, p. 142. 



2 U. S. Biological Survej'. Fourth Provisional Zone Map of North America, by C. Hart Merriam, Vernon 

 BaUey, E. W. Nelson, and E. A. Preble, 1910. 



