Argobuccimun.] GASTROPODA. 31 1 



corresponds with the elevation of the varix. Columella vertical, 

 very little concave. Inner Up spreading beyond it, smooth, narrowed 

 below, and with numerous wrinkles on the inner edge of the canal ; 

 extending over the parietal wall, with a prominent tooth above. 

 Operculum oval, nucleus apical. 



Diameter, 42 mm. ; height, 74 mm. Angle of spire, 50. 



Animal with a yellowish, finely velvety epidermis. Head large ; 

 tentacles long, cylindrical, distant, with the eyes prominent and 

 near their bases. Foot large, quadrilateral, yellowish, and grooved 

 in front. Muzzle cylindrical. Radula rather long, with 5 rows of 

 teeth. There are 2 salivary glands. The male with a long and grooved 

 intromittant organ. (Quoy and Gaimard.) 



Hab. North Island, and Martin's Bay in the South Island ; Bream 

 Bay (Q. & G.) ; Cook Strait (Dr. Dieffenbach) ; Whangarei Heads 

 (C. Cooper) ; Kermadec Islands (T. F. Cheeseman). 



Fam. CASSIDID^, Adams. 



Animal with large head, eyes at the exterior base of the tentacles ; 

 proboscis cylindrical, extensible ; mantle and foot large ; siphon 

 moderately long. Jaws reticulated. Central tooth of radula with 

 several cusps, the median larger ; lateral teeth large, multicuspidate ; 

 marginals falciform, simple or denticulate. 



Shell solid, subglobular or triangular, with short spire ; whorls 

 sometimes varicose ; aperture terminating anteriorly in a short re- 

 curved canal ; columella callous, spread out, usually plicate ; outer- 

 lip margin thickened, dentate within. Operculum corneous, con- 

 centric, elongated, semilunar, the nucleus at the centre of the inner 

 margin. 



The varices of the shell persist in its interior. 



These animals are active and voracious, living in sandy localities, 

 and preying on bivalve molluscs. 



Genus 1. PHALIUM, Link, 1807. 



Phalium, Link, Beschr. Rostock Samml., 1807, 112. Type : Cassis glauca, L. 

 Cassidea, Perry, 1811. Bezoardica a, Schumacher, 1817. Cassis, Bow- 

 dich, 1822. Semicassis, H. and A. Adams, 1853. Casinaria, Fischer, 

 1844. 



Animal having an oval foot, extending beyond the shell, with a 

 marginal groove and a small inferior aquiferous pore ; copulatory 

 organ flattened, ending in a fleshy, hook-shaped appendix, and being 

 grooved the whole length. 



Shell usually rather solid and thick, with the last whorl very large, 

 often varicose ; aperture longitudinal, narrow ; outer lip with a thickened 

 reflected margin, and dentate within ; inner lip rugosely plicate. 



About twenty-five species are known, inhabiting warm seas. 



Fossil in the Tertiary. 



Vernacular Name. Helmet-shell. 



