GASTROPODA. 66 



bicuspid ; the inner cusp single, but constricted near the base, and 

 with a point ; the outer cusp very oblique, notched at the end. Mar- 

 ginals broad, rounded at the ends, with numerous points, the inner 

 one of which is much longer than the rest. (Hutton.) 



Type in the Canterbury Museum, Christchurch. 



Hab. Waiau, Southland, type (G. M. Thomson) ; Waipara ; 

 Waitaki ; Queenstown ; Lake Guy on ; Kaikoura Mountain, high up ; 

 Hossack Downs, Canterbury (E. Suter) ; Ashburton, on flax (W. W. 

 Smith) ; Mount Somers (ibid.) ; Castle N Rock, Southland (A. Hamil- 

 ton) ; Invercargill (W. W. Smith) ; Stewart Island ; Mount Linton. 



Remarks. It is common in limestone districts in the South Island. 

 I am pretty sure that this species is not found in the North Island, and 

 the specimens from localities in the North Island mentioned by Cap- 

 tain Hutton and myself are the, nearly allied T. 



7. Therasia Traversi, E. A. Smith, 1884. Plate 50, fig. 11. 



Helix (Thalassia) Traversi, Sm., P.Z.S., 1884, 274. pi. 23. f. 16, a, h. Champa 

 (Thalassia) Traversi, Sm. : Tryon, Man. Conch. (2), ii, 214, pi. 63, f. 68-70. 

 Geronlia (Therasia) Traversi, Sm. : Pilsbrv. Man. Conch. (2), viii, 71. 

 Thrrasia Traversi, Sm. : Hedley and Suter, P.L.S. N.S.W. (2), vii, 641. 

 Flammnlina (Therasia) Traversi, Sm. : Man. Conch. (2), ix, 16 ; Suter, 

 J. de Conch., xli, 247. 



Shell depressed, subconoid, keeled, narrowly perforate, thin, cor- 

 neous, somewhat glossy. Sculpture : Protoconeh with microscopic 

 distant radiate and indistinct fine spiral lines ; the following whorls 

 with fine arcuate oblique lines of growth, with additional microscopic 

 radial fine lines, crossed by spiral stride, first very close together, but 

 getting more distant as growth and breadth of the whorls increase ; 

 they are present on the upper and under surfaces. Colour corneous, 

 with fine light-red wavy and very oblique lines, retractive on the 

 upper surface, but below the periphery of the last whorl they form 

 suddenly a sharp angle and become pro tractive ; they continue in light 

 zigzag lines to the perforation. Epidermis thin, pellucid, shining. 

 Spire depressed conoidal, lightly convex, about two-thirds the height 

 of the aperture. Protoconeh of If whorls, flattish. Whorls 5^, rather 

 slowly enlarging, a little convex, the last moderately sharply keeled ; 

 base convex. Suture moderately impressed. Aperture oblique, sub- 

 lunate. Peristome thin, sharp. Outer lip angled ; basal lip broadly 

 rounded. Columella short, very oblique. Inner Up a little thickened. 

 expanded and reflexed, continued as an inconspicuous transparent 

 '_ r l;i/t' over the convex parietal wall. Perforation narrow, deep, about 

 one-tenth of the minor diameter in the adult, partly or nearly com- 

 pletely hidden by the columellar reflection. 



Diameter -- Maj., 11-5 mm.; min., 10 mm.: height, 7-5 mm. 



pe). 



Dentition. Suter, P.L.S. N.S.W. (2), viii. 490, pi. 22, f. 5a. 



