626 GASTROPODA. [Pulnwnata. 



convex, periphery of last whorl rounded ; base convex. Suture im- 

 pressed. Aperture oblique, broadly rotimdly lunar. Peristome regu- 

 larly arched, simple, sharp. Columella short, .oblique, arcuate. Inner 

 lip slightly callous, reflexed towards the umbilicus, which is narrow, 

 open. deep, showing 2 volutions. 



Diameter Maj.. 10mm.; min.. 8-8 mm. : height, 5-5 mm. Dia- 

 meter of umbilicus. 1-5 mm. 



Animal with peripodial groove and small caudal pore. 



,ld tc (Plate 1. tig. 7) consisting of numerous vertical, transversely 

 finely striated plaits. 



Radula (Plate 1, fig. 7) has the formula 24 + 6+1 + 6+24. 

 The central tooth has a short heart-shaped reflected portion, with 

 a wide mesocone, not extending to the margin of the basal plate ; 

 no side cusps. The admedians have a strong stout mesocone, at first 

 vertical, but becoming ultimately very oblique and directed inwards, 

 and a minute ectocone ; then follow 5 transitional teeth with basal 

 plates, increasing in size, with small reflected portion and an aculeate 

 mesocone gradually becoming narrower ; finally, there are 19 true 

 marginals, having a small quadrate basal plate, to the inner side of 

 which is attached a long aculeate mesocone with a short projection 

 above. 



The reproductive organs are built up very much on the same plan 

 as in the other species of the genus. 



T/ipe in my collection. 



Hob. Kesolution Island, type (R. Henry). 



HnHftrks. This species is nearest to P. Helmsi, but has much more 

 remote costse and a wider umbilicus. From P. fulminata costata it is 

 distinguished by the more distant and sharp riblets, and the much 

 wider umbilicus. 



4. Phacussa hypopolia, PfeifEer, 1853. Plate 25, figs. 4, 4*7. 46. 



Helix hypopolia, Pfr., M.H. Viv., iii, 1853, 68 ; P.Z.S., 1852 (1854), 148 ; 

 Conch. Icon., vii, pi. 130, f. 787 ; Conch. Cab. (2), i, pi. 161, f. 18-20 ; 

 Man. Conch. (2), ii, 181, 212, pi. 54, f. 15. Charopa hypopolia, Pfr., 

 Nornencl. Hel. Viv., 97. Helix (Charopa) hypopolia, Pfr. : Hector, 

 Cat. Land Moll. N.Z., 9. Patula hypopolia, Pfr., M.N.Z.M., 6. Phacussa 

 hypopolia, Pfr. : Hutton, T.N.Z.I., xvi. 205; Man. Conch. (2), ix, pi. 3. 

 f.' 10, 11 ; Hedley and Suter, P.L.8. N.S.W. (2), vii, G35 ; Suter. .J. de 

 Conch., xli, 243. 



Shell depressed globose, narrowly umbilicated, thin, silky, very 

 closely ribbed. Sculpture consisting of close, thin, sharp, lightly curved 

 axial riblets, about 8 per millimetre, the interstices with fine growth - 

 strije, crossed by fine, microscopic, rather indistinct spiral lines. 

 Colour horny-cinereous, usually radially banded with brown, the bands 

 sometimes zigzag-shaped on the body-whorl, getting obsolete on the 



