80 AMERICAN JOURNAL 



2. Melania tetrica, Conrad. — t. 1, f. 9. 



Description. — -"Tarrited; volutions 9, with oblique angular 

 ribs, crossed by sharp, prominent lines, giving the ribs an 

 acutely tuberculated character; whorls of spire angulated 

 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. 

 I." 



Melania tetrica, Conrad. — Proc. Acad. Nat. Sci., 1850, p. 11. 



Localitrj. — -Rivers of S. E. Australia. 



Observations. — May be compared with M. Aitstralis, Reeve, 

 which is not so high in the spire, with large ribs, which are 

 curved. Australis, moreover, comes from a distant locality- — ■ 

 the rivers of North Australia. 



3. Melania Balonnensis, Conrad. — t. 1. f. 10. 



Description. — "Ovate-elongate, thin, diaphanous; volutions 

 6, those of the spire angulated, 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, f." 



M. Balonnensis, Conrad. — 1. c, p. 11. 

 Locality. — Balonne River, Australia. 



Observations — Of much lighter texture than M. tetrica, also 

 lighter colored, and ribs not so strongly expressed. 



4. Amphipeplea perlevis, Conrad.— t. 1, f. 5. 



Description. — 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, regularly rounded at base." 



Lymnea perlevis, Conrad.— 1. c, p. 11. 



ZocaZ%.— Salamanca and Balonne Rivers, Australia. 



Observations. — Allied to A. Lessonii, but less ventricose, and 

 has flattened sides, while those of the former are convex. The 

 surface is coarsely undulated parallel with the growth-lines. 



