324 THE CHICAGO ACADEMY OF SCIENCES. 



Limnaa, palustris michiganensis WALKER, Nautilus, VI, p. 33, pi. 1, 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. 636, 1902. BLATCH. & 

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



Limnophysa palustris michiganensis BAKER, Journ. Cin. Soc. N. H., XIX, 

 p. 84, 1897. 



Limn&a palustris var. michiganensis CHADWICK, Bull. Wis. Nat. Hist. Soc., 

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



Lymn&a 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. 

 Length. 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 " 



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, Wis. 



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. 



