T finis.] GASTROPODA. 425 



as the aperture. Protoconph small, of 4 smooth and convex whorls, 

 nucleus minute. Whorls 8 to 9, first slowly increasing, the last high ; 

 they are convex and mostly very lightly shouldered ; base somewhat 

 contracted below. Suture superficial, slightly undulating. Aperture 

 subvertical, oval, lightly channelled above, with a very short straight 

 and open canal below. Outer Up convex, sharp, crenulated out- 

 side, thickened and dentate within. Columella vertical and straight, 

 twisted and tapering below. Inner lip broad, extending over the lightly 

 concave parietal wall, usually with a small tubercle below close to the 

 canal. Operculum with a lateral nucleus. 



Diameter, 12 mm. ; height, 24 mm. 



Animal. The anatomy has, I believe, been studied by Kesteven, 

 but I have not seen his publication. 



Hab. Bay of Islands ; Cook Strait. Also Tasmania and Aus- 

 tralia, in depths from 10 to 80 fathoms. 



Remark. The New Zealand habitat of the species was first men- 

 tioned by the late, Justice Gillies (T.N.Z.I.. xiv, 1882, 171). 



Subgen. 3. NUCELLA, Bolten, 1798. 



Nucella, Bolten, Mus. Bolten., 1798, 131 (in part, C'ancellaria excluded). 

 Type: Purpura lapillus, L. Polytropa, Swainson, 1840; not of De- 

 fiance. Polytropalicus, Rovereto, 1899. 



Animal with a small foot ; other characters as in the genus. Den- 

 tition 1 + -|+ 1, the cusps of the central tooth large and of equal size. 



Shell elongately oval ; whorls foliated or tuberculose ; spire 

 acuminate ; the last whorl rounded, excavated above the prominent 

 fascicle ; aperture oval, very little channelled above, produced below 

 into a moderate contracted and recurved canal ; outer lip smooth 

 or lirate within ; columella arcuate, strongly twisted below ; inner 

 lip rather narrow, more or less separated from the fasciole by an um- 

 bilical depression. 



KEY TO SPECIES. 



A. Shell with 9 strong spiral ribs on the body-whorl, interstices narrow ; 



white . . . . . . . . . . . . . . striata. 



B. Shell either with 3 prominent spiral ribs or more than 9 fine narrow 



cinguli on the body-whorl ; brown or orange with white . . scobina. 



4. Thais striata, Martyn, 1784. Plate 45, fig. 18. 



Buccintuii striatum, Mart., Un. Conch., i, 1784, f. 7 ; not of Pennant, 

 1777. Purpura striata, Mart,, Dieff. N.Z., 232 ; Grit. List, 21 ; Malak. 

 Blatter, xix, 1872, 23 ; Miss. I.C., 526. Polytropa striata, Mart. : 

 Mutton, J. de Conch., 1878, 19 ; M.N.Z.M., 56 ; T.N.Z.I., xvi, 221. 

 Bucdnum lacunosunt, Bruguiere, Ency. Meth. (Vers.) (1), 1789, 258. 

 Purpura rugosa, Lam., A.s.V., vii, 1820, 242. P. rupestris, Valenciennes, 

 Voy. "Venus," Moll., pi. 9, f. 1 ; Voy. P.S., 89, pi. 22, f. 23. 



Shell ventricose with an elevated spire, solid, white, spirally lirate. 

 Sculpture consisting of flatly convex spiral ribs, 4 on the penultimate, 

 9 on the body whorl, the deep interstices narrower than the ribs, 



