240 GASTROPODA. [Pectinibranchia. 



Protoconch eroded. Whorls 9 to 10, flattened, regularly increasing ; 

 base nearly flat, excavated round the neck. Suture impressed, some- 

 times margined. Aperture oblique, broadly ovate, channelled above, 

 produced at the base into a short, oblique, and truncated canal. In- 

 terior brown, with a few lighter spiral bands. Outer lip convex, 

 slightly thickened and expanded, sharp. Columella vertical, nearly 

 straight, truncated at the base. Inner lip spreading over a short 

 distance of the columella, sharply limited on the outside, extending 

 over the parietal wall to the spiral ridge, which enters the aperture 

 Operculum normal. 



Diameter, 5 mm. ; height, 14-5 mm. 



Animal unknown. 



Type in the Canterbury Museum, Christchurch. 



Hab. Katikati (type) ; Ngunguru Harbour ; Whangarei : Tiri 

 Tiri Island ; Hauraki Gulf and Auckland Harbour ; Kawhia ; Go- 

 vernor's Bay, Lyttelton ; Chatham Islands (Dr. Dendy). 



Subfam. 2. BITTIIN^. 



Basal lip extended beyond the truncature of the columella ; canal 

 with its slightly expanded margins almost reduced to a sublateral notch. 



Genus 2. BITTIUM, Gray, 1847. 

 Bittium, Gray, P.Z.S., 1847, 154. Type : Strombus reticulatus, Da Costa. 



Animal with a lanceolate foot, subtruncate in front ; eyes placed 

 at the external base of the rather long tentacles ; operculigerous 

 lobe with rudimentary expansions on the sides, siphon rudimentary. 

 Central tooth of radula multicuspidate ; lateral tooth securiform, 

 with the margin denticulate ; marginal teeth long and narrow, ex- 

 tremity pectinate. 



Shell small, elongated, with numerous granular whorls and ir- 

 regular varices ; anterior canal short, not recurved ; outer lip not 

 reflected, usually with an exterior rib ; basal lip extended beyond the 

 canal ; inner lip simple ; operculum 4-whorled, with central nucleus. 



Numerous species, inhabiting temperate waters. 



Fossil in the Cretaceous and Tertiary. 



KEY TO SPECIES. 



A. Aperture with a distinct but short canal. 



a. Body-whorl with 9 to 10 spirals, suture margined ; height 



about 17 mm. . . . . . . . . . . granariui 



aa. Body-whorl with 5 spirals, suture not margined ; height, 



about 4 mm. . . . . . . . . . . litreum. 



B. Aperture without a distinct canal. 



a. Penultimate whorl with 8 spiral grooves ; axial plications 



subobsolete or absent . . . . . . . . Lawleyanum 



aa. Penultimate whorl with 4 nodular spiral ridges . . exile. 



aaa. Penultimate whorl with 3 spiral threads, axial riblets 



distinct . . . . . . . . . . ci/lindricum 



aaaa. Penultimate whorl with 4 cinguli, crossed by about 



20 axial riblets . . . . . . . . retiferuin. 



