64 HELIX-GERONTIA. 



slightly reflected, slightly bent downward. Umbilicus very narrow. 

 (Suter.') Alt. 1, diam 1'5 mill. 



Near Mauriceville, in the bush, North Island, New Zealand. 

 Hyalina allochroida SUTER, Trans. N. Z. Inst. xxii, p. 228, t. 15, 

 f. 14 a-c; with var. sericata, loc. cit., f. 15 a, b, and var. lateumbili- 

 cata, f. 16 a, b. Phrixgnathus allochroida SUTEH, in lit. 



Var. sericata Suter. PL 23, figs. 7, 8, 9. 



Shell very small, depressed, yellowish-horny, thin, pellucid, 

 closely and finely ribbed, ribs bent backwards on the surface, 

 slightly undulating on the periphery ; about 60 ribs in the tenth of 

 an inch (25 per mm.). Spire slightly elevated. Whorls 5, slowly 

 and regularly increasing, narrow, rounded, the last not descending. 

 Suture deep. Aperture oblique, lunar, higher than broad, little 

 excavated by the penultimate whorl. Peristome straight, acute, 

 upper margin somewhat advancing, columellar margin not reflected, 

 obliquely bent downwards. Umbilicus very narrow. 



Diameter 0'05 in. (1-2 mm.), height 0'03 in. (0*7 mm.). (Suter.) 



Under dead leaves and rotten wood in the bush. Found only 



one specimen. North Island; Forty-mile Bush ; Hastwell. (B. $.) 



Var. lateumbilicata Suter. PI. 23, figs. 10, 11, 12. 



Shell very small, depressed, yellowish-horny, shining, pellucid, 

 thin, with rather distant ribs, bent backwards on the surface, oblique 

 and undulated on the periphery. Interstices reticulated. Spire 

 slightly elevated, apex smooth, colorless. Whorls 5, regularly and 

 slowly increasing, narrow, rounded, the last rather descending. 

 Aperture very oblique, rotundly lunar, little excavated by the 

 penultimate whorl. Peristome straight, acute, margins convergent; 

 columellar margin slightly reflected, arcuately bent downwards. 

 Umbilicus open, deep, about one -fifth of the diameter. 



Diameter 0*06 in. (1'5 mm.), height 0'04 in. (1 mm.). 



Amongst dead leaves and mould in the bush. North Island ; 

 Forty-mile Bush ; Hastwell. (H. $.) 



Genus GERONTIA Hutton, 1883. 



This name may be used in an enlarged sense to include all of the 

 New Zealand Helices having a Patuloid shell, a caudal mucus 

 gland and decidedly Patuloid rather than Zonitoid marginal teeth 

 of the radula. For these forms Hutton proposed a family, Charo- 

 pidce; but on the ground that the genus Charopa was founded upon 



