Siphonaria.] GASTROPODA. 601 



lighter ; interior mostly chestnut-brown, the centre yellowish, gene- 

 rally with dark-brown patches ; a narrow marginal line, or often only 

 the tips of the projecting ribs, yellowish. Apex submedian, obtuse. 

 Interior polished, the frontal mantle-scar straight, groove narrow, well 

 marked. Margin mostly undulating, sharp, grooved inside. 



Diameter. 16-8 mm. ; length, 19 mm. ; height. 84 mm. (type). 

 Diameter, 20 mm. ; length, 25 mm. ; height, 9-5 mm. (large specimen). 



Anatomt/. Hutton/A.M.N.H. (5). ix.' 1882. 341. pi. 15; T.N.Z.L, 

 xv. 143. pi 17, f. H-M. 



Dentition. Formula of radula 130 to 140 x 33 to 40 + 1 + 33 to 40 ; 

 the central tooth narrow, with 1 cusp ; laterals about 13, with the 

 mesial cutting-point bidentate and a small cutting-point on the out- 

 side ; marginals with 3 cutting-points, the median the largest, and 

 bidentate on the inner marginals, simple and rounded on the outer 

 ones. 



Type in the Mus. Hist. Nat., Paris. 



Hab. Throughout New Zealand, common ; Chatham Islands. 



Remarks. This is the most variable of our species of the genus, 

 the shell being very often adapted to the surroundings. High conoidal 

 to flattish and oval to semicircular shells are met with. The distinct 

 and projecting primary ribs, the much darker brown colour of the 

 interior, and especially the dentition, separate it from S. australis. 



Subgen. 2. LIRIOLA, Dall, 1870. 



Shell thin and fragile, with fine ribs, which leave the margin entire. 

 Apex marginal or subrnarginal. 



5. Siphonaria lateralis, Gould, 1846. Plate 49, fig. 10. 



Siphonaria lateralis, Gould, P. Bost. S.N.H., ii, 1846, 153; U.S. Expl. 

 Exp., xii, 363, pi. 30, f. 462 ; Pelseneer, Voy. " Belgica," Zool., 

 1903, 9; Strebel, Zool. Jahrb., xxv, 1907, 172, pi. 3, f. 27, 28, 29, 

 29a ; Strebel, Schwedische Sudpolar Exp., 1901-3, vi, pt. 1, 1908, 8. 

 8. redimiculum, Reeve, Conch. Icon., ix, 1856, pi. 5, f. 24 ; E. A. 

 Smith, Trans. Roy. Soc. London, 1879, 16; Button, M.N.Z.M., 36; 

 T.N.Z.L, xv, 143 ; Martens, Deutsche Tiefsee Exp. " Valdivia," 1903, 

 72 ; Melvill and Standen, Trans. Roy. Soc. Edinburgh, xlvi, pt. 1, 142. 

 Kerguelenia redimiculum, Rve. : Rochebrune and Mabille, Miss. Cap 

 Horn, 29. S. (Liriola) tristensis, Leach : Watson, Chall. Rep., xv, 675 ; 

 Button, Index, 68, not of Leach. 



Shell ovate-oblong, rather depressed, apex posterior, turned to 

 the left, surface radiately ribbed, solid, thin at the margin. Sculpture 

 consisting of about 25 distant flatly rounded undulating radial ribs, 

 crossed by fine concentric growth-laminae. Colour reddish or greenish- 

 brown ; interior dark purple, lighter under the apex, but sometimes 

 the latter part is darker, and the margin light brown. Epidermis 

 generally present only near the margin, greenish or brown, horny. 

 Apex posterior, uncinate. bent to the left, near the margin, marginal 

 or extending beyond the margin. Anterior slope convex, left side 



