1)28 GASTROPODA. \Pulmonatn 



KEY TO SPK.( IKS. 



A. Shell impcrforale. Microscopically spirally striate, periphery con- 



vex . . . . . . . . . . . . . . Laingi. 



B. Shell umbilicatc. 



a. Shell with distinct radiate riblets. 



l>. Riblets 2-3 per millimetre, crossed by distant spiral lines . . iyniflua. 



/>!>. Kiblets per millimetre, beset with hairs when fresh, no 



spiral lines . . . . . . . . . . ziczag. 



an. Shell with growth-striae only. 



l>. Protoconch of 1| whorls, microscopically spirally striate; 

 succeeding whorls devoid of spiral sculpture. Peri- 

 phery acutely angled. Umbilicus very narrow, one- 

 fourteenth of the greatest diameter, which is G mm. . . jtropinqtui. 



/i/i. I'rotoronfh of 1 whorl, indistinctly microscopically 

 spirally striate, the succeeding \\lmrl* with the same 

 sculpture. Periphery keeled. I'mbilicus one-ninth 

 of the greatest diameter, which is 9-5 mm. or more . . :<l<nlt-i . 



1. Thalassohelix igniflua, Reeve. IS.")!*. Plate 50. tig. 3. 



Helix iijiiillnu, Kve., Coueh. Icon., vii. pi. 128, f. 774. Thalassohdix igniftua, 

 Hedlcy and Sutcr. P.L.S. X.S.W. (2), vii, 636; Stiter, J. de Conch.. 

 xli. 256. Hrli.r fambfln. I'feiffer. M.H. Viv.. iii, 1853, 84; P.Z.S.. 1852 

 il854), 57: Hector, Cat. Land Moll. N.Z., 9; Button, M.N.Z.M., 11. 

 Kl<ni Ironhda, Pfr.. Man. C.mch. (2). i. 12!). pi. 26. f. 25. 



Shell subconoidly depressed, umbilicated, thin, with radial riblets 

 and spiral lirse, slightly shining, diaphanous, fulvous. Sculpture con- 

 sisting of distant, oblique, retractive, membranous radiate riblets. 

 '2 to 3 per millimetre, crossed by distant spiral strise. extending down 

 into the umbilicus, the points of intersection raised into a short bristle : 

 the interstices between the spiral strise finely microscopically striate. 

 Colour fulvous, sometimes chestnut-spotted or with protractive brown 

 zigzag bands, usually broader upon the base. Spire subconoidal. 

 rather obtuse, about half the height of the aperture. Protoconch of 

 1| smooth convex whorls. Whorls 5 to 5|, first slowly increasing, 

 rather convex, the last not descending, obscurely angled at the peri- 

 phery ; base convex. Suture impressed. Aperture oblique. Innately 

 rotund, within shining. Peristome simple, straight, margins con- 

 vergent. Columella oblique, arcuate. Inner lip thin, expanded above, 

 extending as a thin white callus over the convex parietal wall. Um- 

 liilicus moderate, conical, about one-sixth of the greatest diameter. 



Diameter Maj., 13mm.; min.. llmm.: height. 7mm. AVith 

 the same diameter the height reaches sometimes 9 mm. 



Animal (Hutton, T. N.Z.I., xvi, 165). --The mantle subcentral. 

 slightly reflected over the peristome of the shell : tail pointed, with 

 a. caudal mucous gland, but no papilla ; eye-peduncles approximated 

 at their liases ; colour white, with clusters of brown spots and an in- 

 terrupted brown line round the sides, below which the margin of the 

 foot is striped with brown and white transverse bands ; a streak on 

 each side of the head black: sole ot ihe foot mottled with brown. 



