77*i GASTROPODA. [Puhnonata. 



6. Rhytida Meesoni, Suter, 1891. Plato 50, fig. 13. 



Rhytida Meesoni, Suter, T.N.Z.I., xxiii, 1890 (1891), 84, pi. 16, f. 1, a, b, A ; 

 "Nautilus," vii, 123; Hedley and Suter, P.L.S. N.S.W. (2), vii, 631; 

 Suter, J. de Conch., xli, 286.' Par;//-//",,/,/ Mn-soni. Sut., P.L.S. N.S.W. 

 (2), viii, 487. 



Shell small, depressed, umbilicated. corneous, thin and fragile, 

 pellucid. Sculpture : Protoconch very finely radially striated ; the 

 following whorls are minutely malleated by oblique anastomosing 

 wrinkle-striae, occasionally crossed by a few spiral lines : the whole 

 shell with minute, exceedingly fine, and dense microscopic lines. 

 Colour yellowish-horny, with a greenish hue ; aperture slightly iri- 

 descent within. Epidermis thin and shining. Spire very little raised, 

 flatly convex. Protoconch flat, of H turns. Whorls 3f. convex, the 

 last rapidly increasing, broadening toward the aperture ; periphery 

 and base convex. Suture impressed. Aperture oblique, transversely 

 oval. Peristoine thin and sharp. Outer lip advancing and lightly 

 convex above, narrowly rounded at the periphery ; basal lip lightly 

 arched. Columella oblique, short, arcuate. In tier lip somewhat 

 callous, expanded above ; parietal wall with a very thin shining 

 glaze. Umbilicus moderate, deep, gradate, about one-sixth of the 

 greatest diameter. 



Diameter Maj., 11-5 mm. ; rnin.. 9mm. : height. 6mm. 



Egg small, calcareous, white, elongately oval. Diameter, 2-3 mm. ; 

 length, 3 mm. 



Radula with the formula 12 + 0+ 12 ; the transverse rows of teeth 

 forming an acute angle. Teeth slender, aculeate, increasing from the 

 centre up to the 10th, which is the largest. 



Type in my collection. 



Hob. South Island : Wairoa Gorge, type (Meeson) ; Collingwoocl ; 

 Kenepuru (McMahon) ; Hossack Downs. Canterbury (E. Suter). 



7. Rhytida patula, Button, 1883. Plate 49, fig. i:j. 



Rhytida patula. Huttou, T.X.Z.I.. \v. 1882 (1883), 139 : Hedley and Suter, 

 P.L.S. N.S.W. (2), vii, 630 ; Suter, J. de Conch., xli, 286. 



Shell depressed, umbilicated, thinnish. translucent, scarcely shin- 

 ing, finely malleated, dark-horny. Sculpture : Protoconch radially 

 finely striated, the following whorl radiately plaited, the remainder 

 with numerous small radiate depressions, and a few obsolete broad 

 piral grooves near the periphery, microscopically finely and very 

 distinctly spirally striated. <'i>l.n,-ir mown to olive, yellowish at the 

 apex ; aperture light bluish-white inside. Spire low. broadly convex, 

 obtuse. Protoconch of 1| whorls, flatly convex. Whorls 3|- to 4, 

 rapidly increasing, rounded, the last very large, the last quarter occupy- 

 ing more than half the diameter of the shell ; periphery and base 

 rounded. Suture impressed. Aperture very large, oblique, oblong- 

 oval. Peristome slightly thickened. Outer lip somewhat depressed 

 and advancing above, flattish, narrowly rounded at the periphery ; 



