THE NATURAL HISTORY SURVEY. 177 



of the foot from the head to the posterior extremity, the two 

 ends meeting above the tail where a rounded and prominent 

 mucus gland is formed. This gland has the power of closing 

 and expanding. 



Jaw: "Very arcuate, of almost uniform breadth, ends 

 blunt; anterior surface with transverse striae; concave margin 

 simple, with a well developed, blunt, median projection." ( W. 

 G. Binney.) 



Radula: "Lingual membrane very broad, composed of 87 

 rows of 129 (64-1-64) long, slender teeth each; centrals tri- 

 cuspid; laterals 4, bicuspid, in a straight, transverse row; mar- 

 ginals aculeate, in a somewhat crescentic row. Another mem- 

 brane had 57-1-57 teeth." (W. G. Binney.) 



Genitalia: See under Omphalina. 



Distribution: Southern Canada south to Florida, west to 

 Michigan and Arkansas. 



Geological distribution: Pleistocene; Loess. 



Habitat: In moist, somewhat open woodlands. 



Remarks: A species easily distinguished by its large size 

 and glossy surface. The only locality from which authentic 

 specimens have been obtained is near Maywood, in 1892. Dur- 

 ing the last three years the writer has carefully searched all 

 about that region but without securing a single specimen. It 

 is, therefore, a doubtful species for this region. 



GENUS VITREA Fitzinger. 



Vitrea FITZINGER, Syst. Verzeich, p. 99, 1833. 



Hyalinia AGASSIZ, in CHARPENTIER, Nouv. Mem. Soc. Helv., Vol. I, 



p. 13, 1837. 



Hyalina of BINNEY, TRYON, and other authors. 

 Polita HELD, Isis, p. 916, 1837. 

 Glyphyalinia MARTENS, Biol. Cent. Amer. Moll., p. 117, 1892. 



FIG. 33. 

 Animal of VITREA CELLARIA Muller. (After Binney.) 



Shell: Small, thin, glassy, shining, heliciform; spire gen- 

 erally depressed; aperture rounded or lunate; peristome very 

 thin, acute. 



Animal: With no accessory organs upon the genital sys- 

 tem; dart sac not present; other characters as in Omphalina 

 (Fig- 33)- 



