22 NANTNA. 



N. SCALPTA, Martens. PI. 4, figs. 48-51. 



Perforate, thin, closely striate, decussated by obsolete spiral 

 lines; reddish horn-color; whorls 6, the last angulated on the 

 periphery, the angle becoming evanescent in front. 



Diam. 19 mill. 



Mauritius. 



This is Helix rufa, of Pfr. and Reeve, but not of Lesson, the 

 latter being identical with H. Novde-Hibernise, of Quoy. N. 

 semifusca, Desh. (figs. 50, 51), is probably the same, although 

 the characteristic spiral sculpture is neither described nor 

 shown in the figure. 



Subgenus ROTULA, Albers, 1850. 

 N. LINOPHORA, Morelet. PI. 4, figs. 52, 53. 



Barely perforate, thin, costulate ; corneous brown or greenish, 

 epidermis whitish, chiefly remaining at the suture and below the 

 carina ; whorls, 6. Diam. 12 mill. 



Ins. Bourbon, Mauritius. 



N. SEMICERINA, Morelet. PI. 4, figs. 54, 55. 



Scarcely perforate, costulate-striate, thin ; brownish or green- 

 ish corneous, sometimes with a single brown band above the 

 carina, darker below, with a wide light band beneath the carina ; 

 whorls 6. Diam. 16 mill. 



Mauritius. 



N. JKawsoniSj Barclay, is a synonym. 



N. BIJUQA, Stoliczka. PI. 4, figs. 56-59. 



Narrowly umbilicated, thin, corneous, light yellowish brown ; 

 whorls 5|-6^, suture simple, rarely thread-margined above, 

 closely obliquely costulate, and more or less distinctly crossed 

 by still closer revolving striae, crispate or subgranular, smoother 

 below the peipheral carina, except a couple of impressed spiral 

 striae immediately under it. Diam. IT mill. 



Penang. 



N. ARGENTEA, Reeve. PI. 4, fig. 60. 



Perforate, thin, smoothish, lightly and very minutely decus- 

 sated ; greenish brown, pellucid, with wide silvery epidermal 

 bands ; whorls 6, the last not descending. Diam. 13 mill. 



Mauritius and Isle of Bourbon. 



N. semicerina, var. turbinata, Morelet, is a synonym. 



