i 9 6 DISCOVERY REPORTS 



This species is closely allied to N.finlayi (Powell, 1930, p. 537) from off Poor Knights 

 Islands in 60 fathoms. The present species, however, differs in having more numerous 

 spiral ridges. 



Nobolira manawatawhia, n.sp. (Plate LII, fig. 16). 



Shell small, ovate-conical, solid, white, sculptured with a few heavy spiral keels. 

 Whorls five, including a typical protoconch of two whorls, sculptured with six fine 

 spiral threads. Spire whorls with two equally strong spiral keels, one just above the 

 middle of the whorl and the other near to the lower suture. There is also an incipient 

 or subobsolete third keel, but even on the last whorl it is hardly noticeable. On the body 

 whorl there is in addition to the two main keels a third one proceeding from the lower 

 suture, and three weaker ones on the base. The surface of the shell is crowded with 

 closely spaced microscopic axial growth striae. Spire gradate, about 1 i times height of 

 aperture. Aperture circular. Peristome continuous, thickened externally by a heavy 

 rounded varix. Parietal callus separated from the body-whorl by a narrow groove. 

 Height 2-1 mm.; diameter 1-25 mm. (Holotype). 

 Habitat: Off Three Kings Islands, St. 934, 92 m. 



This species differs from the previously described New Zealand members of the 

 genus in being proportionately broader. 



This Recent species appears to be the direct descendant of the Mid-Pliocene (Nuku- 

 maruan) N. charessa (Finlay, 1926), differing from it in being slightly broader, and in 

 having only two well-developed keels on the spire whorls and three instead of four on 

 the base. 



Genus Estea, Iredale, 191 5 

 Type (original designation) : Rissoa zosterophila, Webster 

 Estea crassicarinata, n.sp. (Plate LIII, fig. 4). 



Shell minute, obtusely conical, solid. Sculptured with heavy spiral keels. Whorls $\, 

 including a low convex protoconch, not clearly marked off from the post-nuclear 

 whorls. Apex of protoconch smooth, but two spiral keels commence after the first 

 half-whorl and continue over the first post-nuclear whorl, but increase to three on 

 second and four on the penultimate. On the body whorl there are, in addition, three 

 spiral keels on the base. The keels are prominent and rounded, and the interspaces are 

 a little less than the width of these keels. Spire twice height of aperture. Aperture small, 

 almost circular. Peristome continuous, edge thin, neither reflected nor variced, but 

 gradually thickened within. There is no umbilical cavity. Colour buff, tip of spire 

 tinged with reddish brown. 



Height 1-5 mm.; diameter o-8 mm. (Holotype). 

 Habitat: Off Three Kings Islands. St. 933, 260 m. 



In spite of the spiral keels, this species is not a Lironoba, for the apertural details are 

 typical of those of Estea, which are quite distinctive. Certainly no other Estea has such 

 prominent carinate sculpture, but a tendency towards heavy spiral ornament is shown 



