598 GASTROPODA. [Pvlmanata. 



produces a slight projection on the margin. External surface radially 

 ribbed. 



Distribution. Warm and temperate seas, the maximum of the 

 species in the Southern Hemisphere. 



Fossil in the Eocene of Paris and Miocene of Piedmont. 



KEY TO SPECIES. 



A. Shell solid ; apex subcentral. 



a. Shell small, length less than 30 mm. 



b. Interior liver-brown, the centre darker. Lateral teeth of 



radula with the mesial cutting-point unidentate . . a ustralis. 

 bb. Interior chestnut, the centre yellowish with dark patches. 

 Lateral teeth of radula with the mesial cutting-point 

 bidentate . . . . . . . . . . zelandica. 



bbb. Interior purplish-brown with a white central spot ; 



surface black, the riblets white . . . . Cookiana. 



aa. Shell large, length more than 30 mm. Interior flesh-colour 



to orange, sometimes greyish . . . . . . . . obliqwata. 



B. Shell thin, fragile ; apex marginal. Apex posterior, uncinate, 



near the margin or extending beyond it . . . . lateralis. 



Subgen. 1. SIPHON ARIA, s. str. 



1. Siphonaria australis, Quoy and Gaimard, 1833. Plate 24, 

 fig. 6. 



Siphonaria australis, Q. & G., Voy. Astrol., ii, 1833, 329, pi. 25, f. 32-34 ; 

 C.M.M., 55; Grit. List, 39; J. de Conch., 1878, 42; M.N.Z.M., 36; 

 T.N.Z.I., xv, 142. 



Shell ovate-oblong, rather conical, with numerous ribs, but little 

 projecting at the margin, interior usually liver-brown. Sculpture con- 

 sisting of numerous unequal slightly undulating ribs, the elevation 

 of the siphonal groove on the right side marked by broad bifurcate 

 ribs, those of the ribs on the right side which reach the summit are 

 wider apart than those on the remaining parts of the shell ; the ribs 

 are raised, sharply rounded, and crossed by very fine concentric growth- 

 lines ; at the margin they are but little or not projecting. Colour 

 exteriorly reddish-brown, the ribs whitish ; interior usually liver- 

 brown, the centre much darker ; outside the muscular scar a narrow 

 light band, followed by a broader darker band, and the margin generally 

 marked with white at the termination of each rib. Apex behind the 

 middle and a little to the left, slightly uncinate in well-preserved 

 specimens ; slope very lightly convex all round. Inside polished, the 

 muscle - scar horseshoe - shaped, the frontal mantle - scar concave. 

 Margin entire, sharp, or slightly denticulate. 



Diameter, 10-5 mm. ; length. 14-5 mm. ; height, 6-3 mm. (type). 

 Diameter, 17 mm. ; length, 22 mm. ; height, 10 mm. (specimen from 

 Stunner). 



Animal pale-yellowish, speckled with black on the sides of the 

 foot and head. 



