324 THE CHICAGO ACADEMY OF SCIENCES. 



Limncca palustris michiganensis Walker, Nautilus, VI, p. 33, pi. l, figs. 

 9, 10, 1892; Rev. Moll. Mich., pp. 7, 18, 1894.— Baker, Trans. Acad. Sci. St. 

 Louis, XL, p. 17, 1901 (part); Moll. Chi. Area, II, p. 276, pi. 31, fig. 25, 1902 

 (part).— Daniels, Rep. Dept. Geol. Nat. Res. Ind., p. 63G, 1902.— Blatch. & 

 Daniels, Rep. Dept. Geol. Nat. Res. Ind., XXVII, p. 596, pi. 1, fig. 12, 1902. 



Limiiophysa palustris michiganensis Baker, Journ. Cin. Soc. N. H., XIX, 

 p. 84, 1897. 



Limncca palustris var. michiganensis Chadwick, Bull. Wis. Nat. Hist. Soc, 

 IV, p. 81, 1906; Nautilus, XX, p. 22, 1906. 



Lymncea palustris michiganensis Baker, Bull. 111. State Lab. N. H., VII, 

 p. 105, 1906. 



Shell : Elongated, narrow, attenuated, rather thin ; periostracum 

 light yellowish horn, frequently jet black; occasionally longitudinally 

 striped; surface dull to shining; sculpture as in palustris; whorls 

 6 to 7, rather evenly increasing in size, typically flatly rounded, espe- 

 cially the body whorl ; spire long and very much attenuated ; sutures 

 usually less impressed than in palustris; aperture elongate-ovate, gen- 

 erally much shorter than the spire ; peristome with heavy varical thick- 

 ening; inner lip narrow, reflected and appressed to the columellar 

 region, forming a distinct plait and usually completely closing the 

 umbilicus ; parietal callus rather wide, heavy. 



^ength. 



Breadth. 



Aperture length. 



Breadth. 





30.00 



12.00 



13.00 



5.00 mill. 



Type umbrosa 



32.00 



12.00 



14.00 



6.50 " 



" elodes 



31.00 



10.50 



12.00 



6.00 " 



White Co., Ind, 



30.00 



11.00 



12.00 



6.00 " 



" " 



30.00 



10.50 



11.50 



5.50 " 



" " 



30.00 



11.00 



12.50 



6.25 " 



" " 



26.00 



9.50 



11.50 



5.50 " 



" " 



21.00 



8.50 



11.00 



4.50 " 



t{ a 



28.25 



9.00 



11.90 



5.50 " 



Lockport, 111. 



28.00 



9.00 



11.00 



5.00 " 



" " 



37.00 



14.00 



16.00 



8.00 " 



Lake Mendota, 



Types : Academy of Natural Sciences, Philadelphia ; elodes, one 

 specimen, No. 58638 ; umbrosa, two specimens, No. 58504 ; michigan- 

 ensis, Walker, coll. Bryant Walker; cotypes, Acad. Nat. Sci. Phil.. 

 No. 58690. 



Type Locality.: Canandaigua Lake, New York, for elodes; 

 waters of the Missouri, near Council Bluffs, Iowa, for umbrosa; Ecorse 

 and Greenfield, Wayne County, Michigan, for michiganensis. 



Animal : Not differing externally from palustris. 



Jaw, Radula and Genitalia: Not differing essentially from 

 palustris. 



Range (Figure 35) : Connecticut to South Dakota; Rainy Lake, 

 Ontario, south to northern Kansas and southern Ohio. 



