BY PROFESSOR F. W. HUTTON, F.G.S. 359 



Habitat. — Auckland to Dunedin. 



Shell with six, sub-equal, nodulose spiral ribs on each whorl 

 above the periphery. Colour purplish white, spotted with darker 

 both on the spire and on the base. 



The dentition is figured in the Trans. N.Z. Institute XIV., 

 pi 7, fig. N. 



Trochus chathamensis. Hutton, Cat. Marine Moll, of N.Z #> 

 p. 36 (1873). 



Habitat.— Wellington (T. W. Kirk) ; Chatham Islands. 



Whorls spirally striated and with a thick sub-nodulose keel at 

 the periphery, above which they are obliquely plaited ; suture 

 margined. Colour white with purplish red markings, the base 

 spotted with red. 



Genus. Zizyphinus. Gray. 



A. whorls flattened. 



Zizyphinos DECARiNATus. Perry, Conchology, Trochus, pi. 47, 

 fig. 2 (1811); Z. Cunninghami, Gray in Griffith's Animal 

 Kingdom, Mollusca, pi. 1, fig. 7 ; Eeeve, Conch. Icon., fig. 6. 

 Habitat. — Cook's Straits to Auckland. 



Shell trochiform, thin ; about ten spiral moniliform lines on 

 the body whorl above the mouth ; umbilical region with a large 

 callosity ; lower surface nearly white. Periphery angled. 

 The operculum and dentition are unknown. 



ZiZYPHiNtrs selectus. Chemnitz, Conch. Cab. XL, figs. 1896-97 

 (1789) ; Peeve, Conch. Icon., fig. 1. Trochus pellucidus, 

 Valenciennes, Voy. de la Venus, Moll., pi. 4, fig. 2. 

 Habitat. — Auckland and Cook's Straits. 



Shell trochiform, thin ; about ten spiral moniliform lines on 

 the body whorl above the mouth, sometimes with smaller smooth 

 lines between them ; umbilical region with a small callus. Base 

 with distant fine sub-moniliform spiral strife ; pale with distant 

 elongated spots. Periphery rounded. 



The dentition is figured in Trans. N.Z. Institute XV., pi. 14, 

 fig. L. 



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