HELIX-CHAROPA. 97 



to be of much value for distinguishing the variety. According to 

 my observations, P. corniculum varies considerably in the number 

 of the ribs in different localities. I collected specimens in the Forty 

 mile Bush with about 50 ribs in the tenth of an inch, and near 

 Wellington with less than 40. Diam. 2'75, height 1/5 mill. 



(Suter, in Trans. K Z. Inst. 1890, p. 89.) 



Foot of Sealy Range, Hooker Valley, South Island, N. Z. 



P. BIANCA Hutton. PL 37, figs. 41, 42. 



Shell minute, discoidal, widely umbilicated, finely ribbed ; color 

 horny brown, banded with darker. Spire flat, or slightly convex ; 

 whorls 4, slowly increasing, rounded, delicately ribbed ; ribs about 

 55 in the tenth of an inch, the interstices striated ; suture impressed, 

 umbilicus broad, gradated ; aperture slightly oblique, rotundly 

 lunar; peristome thin, regularly arched; greatest diameter 'I, least 

 09 inch. (Hutt.) 



Netv Zealand : North Island at Auckland, Horokiwi, Wellington 

 and Hastwell; S. Isl. at Greymouth, Bealey and Hooker Valley . 



P. bianca HUTT., Trans. N. Z. Inst. xvi, p. 175, 192. SUTER. 

 Trans, xxiv, p. 273, 276, 292, t. 21, f. 20, 21 (jaw and dentition), 

 P. bianca. var. montana SUTER, Trans, xxiii, p. 88, t. 17, f. K, L 

 (jaw and dentition). 



Var. MONTANA Suter. Shell larger, darker colored without 

 streaks, the ribs coarser and more distant, about 35 in the tenth of 

 an inch, or 14 per mill. Alt. IT, diam. 2J mill. 



White Horse Hill, Hooker Valley, S. Island, N. Z. ; under dead 

 leaves and rotten wood in the subalpine bush. 



P. bianca is also found in the same locality, but rather scantily, 

 and differing from the type in being never over 2 mill, diam., by 

 having 4 whorls, and by the ribs being more distant, about 50 in- 

 stead of 55 in the tenth of an inch. (Suter.') 



P. TAPIRINA Hutton. Vol. IX, PL 4, figs. 4, 5, 6. 



Shell subdiscoidal, broadly umbilicated, closely ribbed ; color 

 horny brown, sub-radiated with reddish spots. Spire very slightly 

 elevated, flat ; whorls 51-6, slowly increasing, rounded, ornamented 

 with narrow oblique ribs, about 16-20 in the tenth of an inch, the 

 interstices indistinctly striated with growth lines ; suture impressed ; 

 umbilicus about one-fourth the diameter of the shell, funnel-shaped, 



gradated, pervious ; aperture subvertical, rotundly lunar ; peristome 



7 



