84 A MONOGRAPH OF 



wliorls 5, rather convex, last not descending, roundly convex ; umbilicus 

 nearly perspective, about one-third of the diameter ; aperture oblique, 

 roundly-lunate ; peristome straight, simple, acute ; margios distant. 



Variety a. — Pure white. 



Diameter, greatest 2, least 1 J ; height, 1 line. 



Habitat. — Hiion Road, and the lower portion of Mount Wellington, 

 on the ground in damp places. /{jM^t^J^w n^'/ieu. •i^&'itUu^ 



Brazier remarks of this species — '■^ There is a pure white variety of 

 H. Petterdi that may be distinguished as H. Feroni." In form 

 resembling H. Stanleyensis (mihi), but differs in the want of the rays of 

 colour so persistent in that species, in the striae being extremely fine, 

 almost smooth towards the apex, and in the umbilicus being more open. 

 It also ap23roaches H. Tamarensis (mihi) and H. architectonica (Brazier), 

 but is nevertheless easily separated from all. Its most important 

 character is the extreme fineness of the satiny-like strise, T v. -Mm nwii. 

 TTtih "'^"TT Tilt rirti t i ll liii i 1i l j j^i i nj " i ln n il i iii j l l iiii!^ Iilil |i1iiiiiiiil 



52. — Helix ( ) architectonica — Brazier. 



Pro. Zool. Soc, 1872. 



H. Gunnii — Brazier. 

 H. assimilis — Brazier. 



H. spectra — Cox. 



Legrand's Col. for Mon., sp. 64. 



Pro. Royal Soc, Tas., 1876. 



Pro. Zool. Soc, 1872. 

 Legrand's Col. for Mon., sp. 66. 



Legrand's Col. for Mon,, sp. 55. 

 Shell rather widely umbilicated, depressly-orbicular, thin, glassy, 

 shining, regularly and closely arcuately ribbed, the interstices with very 

 fine strise ; spire rather elevated ; suture impressed ; whorls 5, mode- 

 rately convex, descending a little in front ; base convex, sculptured 

 same as upper surface ; umbilicus wide, rather narrow at the bottom ; 

 aperture nearly vertical, roundly-lunate ; peristome simple, thin, acute ; 

 margins approximating. 



Variety a. — Shell discoidal, spire not raised, strise somewhat wider 

 apart. 



Habitat. — Foot of Mount Wellington, Recherche Bay (Legrand 

 Col.), Myrtle Bank (R. M. Johnston). 



This species differs from H. Petterdi (Brazier), its nearest ally in 

 form, by its coarser ribs and sculjDtured interstices. It also resembles 

 H. Stanleyensis (mihi J ; the principal difference is the want of the 

 strong decussation so persistent in that species. I think, however, it 

 may be but a variety, although the colouration is so totally different. 

 It is not gregarious like that species, and is never found associated with 

 it. I have not a typical 11. assimilis or H. spectra, but the descriptions 



