Siphonaria.] GASTROPODA. 599 



Anatomy (Hutton, A.M.N.H. (5), ix, 341 ; T.N.Z.I., xv, 142, pi. 17, 

 f. E-G). Jaw arcuate, rounded at each end, concave margin papil- 

 late, remainder of surface reticulate. Radula having the formula 

 160 x 36 + 1 + 36 ; central tooth long and narrow, unicuspidate ; 

 laterals about 19, with a mesial unidentate cutting-point and a small 

 outer cutting-point ; marginals with 3 cutting-points, the mesial 

 large. 



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



Hab. In roots of D'Urvillcea utilis : Cook Strait, type (Q. & G.) ; 

 Sumner. New Brighton. &c. 



2. Siphonaria Cookiana, Suter, 1909. Plate 24, figs. 7, la, 76. 



Siphonaria Cookiana, Sut., P. Mai. S., viii, 1909, 258, pi. 11, f. 18. 



Shell small, solid, oval, depressed conoidal, radiately ribbed, with 

 subcentral apex. Sculpture consisting of about 17 smooth rounded 

 primary ribs, extending from the summit to the margin ; the interstices 

 with 1, rarely 2 or 3, secondary riblets which do not reach the apex ; 

 the anterior primary rib above the siphonal groove is thicker than the 

 others, and divided by a median groove ; growth-lines fine, close, 

 concentric. The riblets are sometimes projecting a little at the margin. 

 Colour black, the riblets white on approaching the base, but usually 

 the shell is greyish- white, the interstices dark brown ; interior purplish- 

 brown, polished, the groove white, usually with a broad oval white 

 spot at the centre, the margin white or white and brown. Apex 

 sharply rounded, more or less eroded, situate a little behind the middle 

 and to the left ; slope lightly convex all round. Interior with the 

 muscle-scar horseshoe-shaped, interrupted on the right side by the 

 shallow groove. Margin sharp, lightly laciniate. 



Diameter, 9 mm. ; length, 12 mm. ; height, 4-5 mm. 



Animal unknown. 



Type in my collection. 



Hab. Lyall Bay, Cook Strait (Miss Mestayer) ; Preservation Inlet. 



Remarks. It is allied to S. exulorum, Hanley, from Norfolk Island, 

 which, however, is a thinner, more depressed species, with more nume- 

 rous riblets, and without the interior white central spot and the white 

 groove. S. amara, Hutt.. from New Guinea, is also a near relation, 

 but also with more numerous riblets, and devoid of the white central 

 spot. 



3. Siphonaria obliquata, Sowerby, 1825. Plate 48, fig. 9. 



Siphonaria obliquala, Sow., Cat. Coll. Tankerville, 1825, app. 7 ; Conch. 

 Icon., ix, f. 56 ; M.N.Z.M., 36 ; T.N.Z.I., xv, 141. S. scutellum, Des- 

 hayee, Guerin's Mag. Zool., 1841, pi. 35 ; Dieff. N.Z., 248. S. diemen- 

 ensis, Quoy : Huttou, C.M.M., 55 ; not of Quoy and Gaimard. 



Shell large, solid, oblong, conoidal, with tubercled radiate ribs. 

 Sculpture consisting of about 20 to 25 bifurcating ribs, nearly all of 

 which descend from the summit ; in young examples they are very 



