Hutton. — On the New Zealand Siphonariidae. 141 



growth-lines ; suture impressed : umbilicus very narrow, but open : aper- 

 ture, peristome, operculum and dentition like the last species. Height 0-13, 

 diameter 0'08 inch. 



Hah. Greymouth, with the last species (Mr. E. Helms). 



More acute than the last and not carinated, but perhaps only a variety. 



Art. IX. — On the New Zealand Siphonariidae. By Professor F. W. Hutton. 

 [Read before the Philosophical Institute of Canterbury, 1st June, 1882.] 

 Plate XVII. 

 In this paper I have attempted to give descriptions of the shells and denti- 

 tion and some notes on the anatomy of all the New Zealand species of 

 Siphonaria and Gadinia known to me, that is four species of Svplwnaria 

 and one of Gadinia : it will I hope form a basis for a comparison with the 

 species inhabiting Tasmania, Australia, and Polynesia. 

 Genus Siphonaria, Blainville. 



Shell conical, with an internal siphonal groove on the right side. Head 

 with a frontal bilobed disc ; eyes none ; pulmonary cavity with a gill lying 

 transversely across the middle ; respiratory orifice covered by a fold of the 

 mantle. Jaw horny. Eadula long, the teeth quadrate, arranged in very 

 slightly curved transverse rows. 



Ova in white gelatinous rope-like masses from an inch to an inch-and- 

 a-half in length, attached to rocks in semicircles or irregular curves. 

 Larva a veliger in a nautiloid operculated shell. 



Ova laid early in February.* 



Siphonaria obliquata. Plate XVII., figs. A to D. 



Siphonaria obliquata, Sowerby, Cat. Coll. Earl of Tankerville, 1825, app. p. 7. 



Eeeve, Conch., Icon., fig. 56. 

 Siphonaria scutellum, Deshayes in Guerin's Magasin de Zoologie, 1841, pi. 35. 



Shell large, oblong, rather depressed, with numerous rather undulating 

 ribs ; apex posterior, uncinate. Exterior brown ; interior liver-brown, often 

 mottled with yellowish-brown. Length 1*6, breadth 1, height -5 inch. 



Dentition, 68 ~g~ 68 . Jaw arcuate, expanded at each end, with about 

 five rounded transverse ribs in centre ; anterior margin papillate, the rest 

 smooth. Central tooth broad, the breadth being more than half the length ; 

 laterals 30 with a unidentate cutting-point on the principal cusp, and a 

 small cutting-point on the outer side which is placed on a small cusp on 

 the more central laterals ; marginals nearly square with three cutting- 

 points, the median one large and rounded at the end. 



* The following species are omitted as not really inhabiting New Zealand : — 

 S. cancer, Eeeve ; inhabits Formosa. S. spinosa, Eeeve ; habitat unknown. 



