HELIX-RHAGADA. 187 



colored ; peristome expanded, a little thickened within, the colu- 

 mellar margin shortly arcuate, dilated, reflexed, appressed. (-Pff.) 

 Alt. 7?, greater diam. 13, lesser 11 mill. 



Torres Straits, northeast Australia. 



H. dringi PFR. Symb. iii, p. 73 ; Monogr. Hel. Viv. i, p. 289. 

 REEVE, Conch. Icon. f. 769. Cox, Monogr. Austr. L. Sh. p. 64. 



Not seen by Cox, nor by the writer. The locality requires con- 

 firmation. 



H. TESCORUM Benson. Vol. IV, pi. 36, fig. 34. 



Shell imperforate, conoid-globose, solid, whitish, irregularly stri- 

 ated ; spire conoid, rather obtuse ; suture deeply channeled ; whorls 

 5?, a little convex, the last rotund, deflexed in front. Aperture 

 diagonal, round-lunar ; peristome thickened, the right margin 

 slightly expanded, basal margin reflexed, columellar margin dila- 

 ted, appressed. (-Pfr.) 



Alt. 13, greater diam. 191, lesser 17 mill. 



Shark's Bay, western Australia. 



H. tescorum BENS. Ann. Mag. N. H. 2d Ser. xi, p. 30. PFR. 

 Monogr. iv. p. 233. KEEVE, Conch. Icon. f. 1154. 



H. ELACHYSTOMA Von Martens. PL 11, figs. 41, 42, 43. 



Shell imperforate, subdepressed, rather thin, most minutely de- 

 cussated with light oblique and spiral striae, somewhat shining, 

 white, with a number of yellowish bands ; spire shortly conoid ; 

 whorls 5, slowly increasing, a trifle convex ; suture moderate ; last 

 whorl rotund, base flattened ; a little descending in front. Aperture 

 small, very oblique, lunate-rounded, peristome thin, a little expanded, 

 sublabiate with white inside ; lower margin straight, columella short, 

 spreading in a subcircular rather thick central callus. (Mart.) 



Alt. 12, greater diam. 19, lesser 16 mill. ; apert. width 8, alt. 8 

 mill. 



Mermaid Strait, Northwest Australia. 



H. elachystoma MART. Monatsb. der K. Preuss. Akad. Wissen- 

 schaften, Berlin, 1877, p. 273, t. 1, f. 8, 9 ; Novit. Conch, v, p. 35, t. 

 144, f. 1-4. 



Far more depressed than H. convicta, and smaller. 



H. CONVICTA Cox. PI. 14, fig. 65 (typical) ; pi. 35, figs. 8, 9, 10 ; 



pi. 30, figs. 7, 11. 



Shell of a compact, depressed-globose form, imperforate, solid, 

 white, with a translucent band at the periphery; surface very 

 delicately striate, nearly smooth. 



