172 THE CHICAGO ACADEMY OF SCIENCES. 



Limnaa strigosa BINNEY, Check-list, p. 12, 1860 ; Land & F. W. Sh. N. A., 

 II, p. 35, fig. 41, 1865; Journ. de Conch., XV, p. 427, 1867. TRYON, Con. Hald. 

 Mon., p. 89 (63), pi. 16, fig. 4, 1872. 



Lymnea coarctata LEA, Proc. Amer. Phil. Soc., II, p. 33, 1841; Trans. 

 Amer. Phil. Soc., IX, pp. 11, 12, 1844. Obs., IV, pp. 11, 12, 1848. 



Lymncea coarctata, WHEATLEY, Cat. U. S. Shells, p. 23, 1845. MORSE, 

 Amer. Nat. Ill, pi. 11, fig. 14, 1870. SCUDDER, Bull. Nat. Mus., 23, pp. 33, 200, 

 1885. 



Limnaa coarctata BINNEY, Check-list, p. 12, 1860; Land & F. W. Sh., N. A., 

 II, p. 35, fig. 42, 1865. TRYON, Con. Hald. Mon., p. 89 (63), pi. 16, fig. 5, 1872. 

 Sows., Conch. Icon., XVIII, Limnsea, sp. 36, pi. X, fig. 36 b., 1872. 



Neristoma coarctata TRYON, Amer. Journ. Conch., I, p. 249, 1865. 

 Lymncea columella var. coarctata, JAY, Cat., Ed. 4, p. 268, 1852. 

 tLymnaus columellus var. a. SAY, Journ. Acad. Nat. Sci. Phil, I, p. 14, 

 1817. BINNEY, Reprint, p. 65, 1858; L. & F. W. Sh. N. A., II, p. 33, 1865. 



Limncea columella var. casta SIMPSON, Proc. Daven. Acad. Sci., V, p. 69, 

 1886. 



SHELL : Elongate-ovate, compressed, thin but generally not frag- 

 ile ; color light greenish to black ; sculpture as in columella ; whorls 

 4-4j^, flat-sided and compressed; body whorl occupying about four- 

 fifths of the length of the shell; spire short, acutely pyramidal; in 

 some specimens a channel is developed in the suture of the whorl; 

 aperture elongate-ovate, rounded anteriorly and angled posteriorly; it 

 is generally very effuse anteriorly and typically somewhat expanded; 

 inner lip strongly appressed to the parietal wall, where a thin, spread- 

 ing callus is developed ; the lower part of the columella is deeply exca- 

 vated and rolled upwards, permitting an anterior view of the shell 

 almost to the apex ; axis feebly gyrate, but columellar plait well marked ; 

 the umbilicus is generally tightly closed. 



Length. Breadth. Aperture length. Breadth. 

 15.00 8.00 11.00 6.00 Mill. Chalybea type 



11.00 7.00 10.00 6.00 " 



14.25 7.50 9.00 4.10 " Coarctata " 



18.75 10.00 12.25 6.00 " Strigosa 



17.00 9.00 12.00 7.25 " Cambridge, Mass. 



16.50 8.50 11.00 7.00 " 



16.50 8.00 12.00 6.75 " Kent, Ohio. 



17.50 10.00 12.75 6.50 " Blount Co., Tenn. 



22.25 11.25 15.00 9.00 " New York. 



20.50 10.00 14.00 8.25 " 



TYPES: Chalybea Gould, 14 specimens, N. Y. State Museum, 

 Albany, No. 301, Gould, No. A3039 ; strigosa Lea, 3 specimens, Lea. 

 Coll., Smithsonian No. 118648, Lea's figured specimen measured above ; 

 coarctata Lea, 3 specimens. Lea Coll., Smithsonian No. 118665. Meas- 

 ured specimen is Lea's original figured example and also Binney's 

 figure 42. 



