344 THE CHICAGO ACADEMY OF SCIENCES. 



Limnaa zebra Tryox, Amer. Journ. Conch., I, p. 228, pi. 23, fig. 4, 1865; 

 Amer. Journ. Conch., Ill, p. 196, 1867. — Ci/rrier, Kent. Sci. Inst., Mis. Pub., 

 Xo. 1, 1868— Tryox, Con. Hald. Mon., p. 94 (68), pi. 16, fig. 14, 1872.— Calkins. 

 Cin. Quart. Journ. Sci., 1, p. 243, 1874; Cin. Quart. Journ. Sci., 1, p. 323, 1874.— 

 Tryox, Home & Science Gossip, June 15, 1881. — Marsh., Conch. Exch., II, p. 

 104, 1887.— Sxyder, The Museum, III, p. 12, 1896. 



Liiiuiophysa zebra Currier, Amer. Journ. Conch., I. p. 294, 1865. — Tryox, 

 Amer. Journ. Conch., I, pp. 68, 70, 250, 1865. — Call, Bull. Wash. Coll. Lab. 

 N. H.. I, p. 53, 1885.— Keyes, Bull. Essex Inst, XX, p. 70, 1888. 



Lhnnea reflexa var. zebra Witter, Quart. Journ. Conch., I, p. 386, 1878. — 

 Walker, Journ. Conch., II, p. 330, 1879. 



Limnophysa reflexa var. zebra DeCamp, Kent. Sci. Inst., Mis. Pub., Xo. 5, 

 p. 8, 1881. 



Limucea reflexa zebra Walker, Xautilus. VI, p. 32, 1892; Rev. Moll. Mich., 

 p. 7. 1894.— Sargext, Xautilus, IX, p. 127, 1896. 



Shell : Elongated, attenuated, thin ; periostracum light corneous 

 or honey-yellow, sometimes streaked zebra-like ; surface dull to shining, 

 growth lines distinct, crowded, crossed by numerous very fine incre- 

 mental stride ; nuclear whorls 1%, small, similar to those of palustris 

 in outline, light corneous to very dark brown in color; whorls six to 

 seven, very flat-sided, the last a little over one-third the length of the 

 entire shell ; spire long and very acutely attenuated, forming an almost 

 unbroken, acute triangle in typical specimens ; sutures impressed, fre- 

 quently margined below by a white band edged with chestnut ; aperture 

 elongate-ovate, narrow, oblique, slightly contracted at the upper part; 

 rounded at the lower part ; peristome sharp, thin, a rather heavy callus 

 within which is dark chestnut colored, the remainder of the aperture be- 

 ing brownish or horn color ; this color shows on the outside as a light 

 band in many specimens ; inner lip very narrow, erect, reflected over the 

 umbilicus, completely closing it; the callus on the parietal wall is well 

 marked and is so heavy in some specimens, especially when slightly 

 raised, as to render the aperture continuous ; the axis is slightlv twisted. 

 frequently somewhat gyrate. 



Length. 



Width. 



Aperture length. 



Width. 





37.00 



11.50 



14.00 



6.25 mill. 



Type exilis. 



37.00 



11.00 



14.00 



6.00 " 



Chicago. 



28.00 



9.50 



12.00 



4.50 " 



Type zebra. 



30.00 



9.00 



13.00 



5.00 " 



Chicago. 



24.00 



7.50 



10.50 



4.50 " 



" 



28.50 



7.50 



11.50 



4.50 " 



" 



28.00 



7.50 



11.00 



5.00 " 



Mercer Co.. 111. 



33.00 



9.50 



12.50 



5.50 " 



Winnebago Co., Ill 



36.50 



10.00 



15.00 



6.50 " 



" " " 



28.00 



9.00 



13.00 



5.50 " 



Antrim Co.. Mich. 



39.00 



11.00 



16.00 



6.00 " 



Minneapolis. Minn. 



30.10 



9.10 



12.in 



4.00 " 



Poland, Ohio. 



