Hutton. — On new Tertiary Shells. 321 



Locality. Wanganui and Petane. 



Rissoa semisulcata. 



Shell minute, pupiform, thick. Whorls 5, flattened ; the first three or 

 four smooth ; the last, or the two last, smooth anteriorly, but with four 

 shallow but well marked spiral grooves on the posterior half. Suture 

 distinct. Aperture roundly ovate, not notched anteriorly ; peristome con- 

 tinuous. 



Length, '1 inch. 



Locality, Wanganui. 



Rissoa rugosa. 



Shell robust, pupiform, roughish. Whorls 6 or 7 ; the first \\ polished, 

 the others of the spire longitudinally plicated with one spiral rib and a 

 sulcus behind and two in front of the plications ; plications more or less 

 nodulose. Body whorl sometimes not longitudinally plicated, the posterior 

 half with about 8 spiral ribs, the anterior half smooth. Aperture broadly 

 ovate, the peritreme continuous and rather patulous. 



Length, '17 inch. 



Locality. Petane. 



Rissoa impressa. 



Shell small, pupiform. Whorls 5, the two first smooth ; the others 

 longitudinally plicated ; base of the body whorl smooth ; a single spiral 

 groove just below the suture, which is margined. Aperture broadly ovate ; 

 peritreme continuous and rather patulous. 



Length, -08 inch. 



Locality. Petane. 



Rissoa graclata. PI. xviii., fig. 21. 



Shell small, ovate, cancellated. Whorls 5, gradated ; the two first 

 smooth and polished ; the others longitudinally and spirally ribbed. 

 Longitudinal ribs about 15 in a whorl. Spirals — a posterior one near the 

 angle, and two anterior ones with a smooth band between. On the body 

 ■* whorl there are about 7 spirals in front of the smooth band and the longitu- 

 dinals become obsolete. Suture impressed. Aperture roundly ovate, not 

 notched in front ; peritreme continuous. 



Length, - 1 inch. 



Locality. Wanganui and Petane. 



Scalaria nympha. 



Shell small, turreted. Whorls slightly rounded, very finely spirally 

 striated and longitudinally ribbed. About 18 or 20 ribs and one or two 

 varices in each whorl. Suture impressed. Body whorl keeled anteriorly, all 

 the longitudinal ribs ending abruptly at the keel ; the base slightly concave 

 and smooth below the keel. Aperture sub-rotund. 

 21 



