THE NATURAL HISTORY SURVEY. 209 



volving brownish bands, one just above and one just below the 

 periphery, the latter being gracefully rounded and never cari- 

 nate; sutures impressed; apex of shell smooth, without striae, 

 which begin toappear on thesecond whorl; whorls six, rounded, 

 regularly increasing; spire elevated, convex; aperture rounded, 

 somewhat lunate, white and pearly inside, with the two revolv- 

 ing bands showing distinctly; peristome sharp, simple, the 

 terminations connected by a thin callus; columella somewhat 

 dilated, subreflected; base rounded; umbilicus round, deep, 

 showing the volutions very plainly to the apex. 

 Gr.diam., 26.00; lesser, 23.00; height, 20.00; umbilicus diam., 5.50 mill. (7716.) 

 26.00; " 22.00; " 19.00; " " 5.50 " (7718.) 



23.00; " 21.00; " 15.50; " " 5.00 " (12393.) 



Animal: Not examined (Fig. 49), but similar in form to 

 alternata. 



FIG. 49. 

 Animal of PYRAMIDULA SOLITARIA Say. (After Binney.) 



Jaw : "Long, low, slightly arcuate, ends but little attenu- 

 ated, anterior surface striate, but without ribs; a median pro- 

 jection to the cutting margin." 



Radula: "The lingual membrane has 25-1-25 teeth, with 

 14 perfect laterals. The transition to marginals is very grad- 

 ual." (Binney, Man., p. 255.) The teeth are similar to those 

 of alternata. 



Genitalia: "The penis sack is short, stout, receiving near 

 its apex the retractor muscle, above which it rapidly decreases 

 in size, and at its apex receives the vas deferens; the last named 

 organ is very peculiar in being greatly convoluted before enter- 

 ing the penis sac; the genital bladder is small, globular, on a 

 long duct, whichbecomes swollen at the lower end; the epididy- 

 mis is convoluted in its entire course."* 



Distribution: Mississippi and Ohio Valleys; Northern 

 Idaho; Eastern Oregon, etc. (Pilsbry); Washington (Hemp- 

 hill). 



Geological distribution: Pleistocene; Loess. 



*Binney, Man. Amer. Land Shells, p, 255. 



