HELIX-CHAROPA. 101 



Umbilicus broad, deep, showing the last whorls, about one-quarter 

 of the diameter. (Suter~) Alt. 1, diam. 2 mill. 



Mauriceville, North Island, New Zealand, in the mould under 

 dead leaves ; very scarce. 



P. raricostata SUT., Tr. N. Z. Inst. xxii, p. 226, t. 14, f. 9. 



The shell is always covered with mud. 



P. MUTABILIS Suter. PI. 19, figs. 25, 26, 27. 



Shell subdiscoidal, depressed, umbilicated, white, sometimes horny, 

 irregularly streaked with rufous, but the white form seems to be 

 predominant ; faintly shining, rather thin, transparent ; with sharp, 

 rather distant arcuated plaits, directed strongly forwards on the 

 upper surface, slightly undulating on the side, the interstices with 

 numerous fine growth-lines. Ribs about 13 in the tenth of an inch 

 (5 per mm.). Spire slightly elevated, flat. Whorls 5^, narrowly 

 rolled up, very slowly increasing, rounded, the last not descending. 

 Suture deep. Aperture slightly oblique, rotundly-lunar, somewhat 

 excavated by the penultimate whorl. Peristome straight, acute, 

 tapering, columellar margin straight, not reflected. Umbilicus 

 broad, perspective, showing all the whorls, about one-third of the 

 diameter. Diam. 3, height I'd mill. (Suter.) 



South Island, N. Z., at White Horse Hill, and foot of Sealy 

 Range, Hooker Valley, under rotten wood, dead leaves, and in 

 mould in the subalpine bush. 



P. mutabilis SUT., Tr. N. Z. Inst. xxiii, p. 84, t. 16, f. 2, a, b, 

 (shell), B, C (jaw and dentition.) 



This species seems to be closely allied to Helix eastboumensis, 

 Beddome and Petterd, from Tasmania, but in the latter the ribs on 

 the upper surface are nearly straight, not arcuated ; the spire is 

 more elevated and not flat, and the umbilicus rather narrower and 

 deeper. But there also occurs a perfectly white and a darker 

 streaked form. 



Animal : Jaw finely striated, arcuated, not tapering, with a 

 slight median projection. 



P. STERKIANA Suter. PI. 19, figs. 28, 29, 30. 



Shell subdiscoidal, depressed, umbilicated, gray-yellowish, with 

 very irregular rufous streaks and dots, sometimes tessellated or 

 forming zigzag lines ; not shining, rather solid, transparent ; with 

 very fine rib-like arcuated stria3, directed forwards on the upper 



