1850.] 11 



scalariform, ventricose ; epiilermls olive, polished, with minute obsolete revolv- 

 ing lines ; body whorl subcarinated in the middle ; aperture suboval. f. J. 

 Local. Parling river, Australia. 



THYSA. 



P. pectorosa. Subovate ; volutions 4 or 5 ; spire short; apex eroded ; penulti- 

 mate whorl ventricose; columella with a prominent, compressed, triangular, 

 oblique tooth or fold ; epidermis olivaceous, clouded with brown. I. h. 



Local. Bogan river, Australia. 



P. Australiana. Elliptical, thin, diaphanous; volutions 4 or 5, regularly con- 

 vex; spire short; epidermis amber-colored ; columella with a slender prominent 

 fold, which revolves within to the apex; margin of labrum regularly curved or 

 rounded. I. I. 



Local. Bogan river, Australia. 



MELANIA. 



M. tetrica. Turreted ; volutions 9, with oblique angular ribs, crossed by 

 sharp prominent lines, giving the ribs an acutely tuberculated character ; whorls 

 of spire anguiated above the middle, and destitute of revolving lines above the 

 angle; ribs on body whorl not continued to the middle of the volution; the 

 revolving lines about 12 in number; 4 on the penultimate volution; aperture 

 ovate-acute, slightly oblique. 1. 



Local. Rivers of Australia. 



M. Balonnensis, Ovate-elongate, thin, diaphanous ; volutions 6, those of the 

 spire anguiated, obliquely ribbed; revolving lines distinct, but little prominent; 

 the ribs on body whorl short ; aperture elliptical, nearly half the length of the 

 shell ; epidermis pale straw-color, with unequal spots of reddish-brown. |. 



Local. Balonne river, Australia. 



LYMNEA. 



L. perlevis. Ovate, thin and fragile, pellucid ; volutions 5 ; spire very short, 

 the whorls convex ; body whorl slightly flattened on the side and also near the 

 suture; epidermis straw-colored; columella with a prominent slender very 

 oblique fold revolving within to the apex ; aperture large, patulous, ovate, regu- 

 larly rounded at base. 



Local. Salamanca and Balonne rivers, Australia. 



The following resolution was adopted : 



Resolved, That in future, visitors will not be admitted to the Museum 

 on other than public days, (Tuesdays and Fridays,) unless accompanied 

 by a member of the Society. 



ELECTION. 



Mr. Samuel M. Fox, of Philadelphia, was elected a Member of the 

 Academy. 



