596 GASTROPODA. [Puluionata. 



Genus 1. AMPHIBOLA, Schumacher, 1817. 



Amphibola, Schum., Essai Nouv. Syst. Habit. Testaces, 1817, 58, 190. 

 Type: A. australis, Schum. (= crenata, Mart.). Ampullacera, Quoy and 

 mard, 1832. Thallicera, Swainson, 1840. 



Head large, flattened ; eyes at the upper sides of the very small 

 tentacles, outside the snout ; foot short, quadrilateral. 



Shell thick, subglobose, and rugose ; spire somewhat depressed ; 

 outer lip with a deep sinus posteriorly ; inner lip callous and ex- 

 panded ; columella broad and reflected at the base ; umbilicus large. 

 Operculum horny, ovate, subspiral. 



Distribution. Australasia, Polynesia. Indian Ocean. 



1. Amphibola crenata, Martyn, 1784. Plate 49, figs. 9, 9o. 



Limax crenata, Mart., Un. Conch., ii, f. 69. Helix crenata, Gmelin, Syst. 

 Nat., ed. xiii. 3623. Bulimus avellana, Bruguiere, Encycl. Meth. (Vers.), 

 i, 1789, 297. Helix avellana, Gmelin, Syst. Nat,, ed. xiii, 3640. Am- 

 pullacera avellana, Quoy and Gaimard, Voy. Astrol., ii, 1832, 196, pi. 15, 

 f. 1-9. Thallicera avellana, Swainson, "Malacology," 1840, 196. Am- 

 phibola avellana, Gmelin, C.M.M., 58 ; M.N.Z.M., 35. A. australis, 

 Schum ,cher. Essai Nouv. Syst. Habit. Testaces, 1817, 190. 



Shell subglobose, thick, whorls shouldered and keeled, rugosely 

 plicate, unibilicate. Sculpture consisting of a rounded keel at the 

 angle of the shoulder, and another, much less distinct, on the middle 

 of the shoulder ; a number of distant spiral cords on the periphery 

 of the body-whorl, and a strongly raised keel round the umbilicus ; 

 the axial sculpture consists of distant sharp and strongly undulating 

 lamellae, continued over the umbilical keel, and entering the unibilicus ; 

 they sometimes reticulate the spirals on the body-whorl. On the spire- 

 whorls the axial sculpture is usually much less distinct. Frequently 

 the whole sculpture is more or less obsolete, the shells nearly smooth. 

 Colour yellowish or reddish-brown ; aperture chestnut, with indications 

 of brown spiral bands above and below the sinus of the outer lip ; 

 peristome white inside, inner lip mostly brown or purple. Spire very 

 short, conoidal, gradate, its height usually a little more than half the 

 height of the aperture. Protoconch small, raised, smooth, the nucleus 

 globose. Whorls 6^, with a slightly convex shoulder, body-whorl large, 

 flatly convex at the periphery, base rounded. Suture well impressed. 

 Aperture semicircular, oblique, broadly angled above, regularly rounded 

 below. Outer Up strongly convex, thickened inside, especially toward 

 the base, with a sharp edge and a moderately deep broadly rounded 

 sinus at the angle of the shoulder. Columella very short, excavated, 

 broadly rounded. Inner lip thick, rather broadly expanded upon the 

 pillar, and extending over the lightly convex parietal wall. Umbilicus 

 narrow, deep, partly covered by the reflected inner lip. Operculum 

 dark brown, horny, with an apical nucleus and radiate strife and 

 plications. 



Diameter, 25 mm. ; height, 28 mm. 



