THE CHICAGO ACADEMY OF SCIENCES. 
ra) 
Ou 
oo 
so appressed at its junction with the parietal wall as to form a pseudo- 
plait; the inner edge of the outer lip frequently forms a rib-like varix 
in very old specimens. 
Length. Breadth. Aperture. Breadth. 
3.25 2.00 1.50 1.00 mill. (Lake James) Type 
4.00 2.00 2.00 UO) 3 y 
3.00 2.00 1.25 190s 3 o re 
4.25 2.00 15: BOO} ss ie e 
4.50 2.50 2.00 HQ) she (Scalariform) 
Osho 2.75 2.00 1.25 Rockford 
4.00 2.10 2.00 1.10 4: 
Types: Chicago Academy of Sciences, No. 23125; cotypes, 
Academy of Natural Sciences, Philadelphia; Smithsonian Institution, 
Washington. 
Tyre Locarity: Marsh, west side Lake James, Steuben County, 
indiana. 
ANIMAL, JAW, RADULA and GENITALIA: Not examined. 



Dstribution of 
— GALBA DALLI. 



RANGE (Figure 24): Ohio to northern Michigan and Montana, 
south to Kansas and Arizona. 
In general, dalli occupies a large part of the Transition and Upper 
Austral life zones; it reaches the Canadian zone in Michigan. It is 
typically an inhabitant of the Upper Mississippian region, reaching 
here its greatest degree of perfection. It has migrated south and west 
into the Coloradoan region. So little is known concerning the distri- 
