646 GASTROPODA. [Palmonat-a. 



13. Allodiscus Tullia, Gray, 1850. Plate 25, fig. 15, a, b. 



Nanina Tullia, (Gray, P.Z.S., 1849 (1850), 165 ; A.M.N.H. (2), vii, 65. 

 Helix Tullia, Gray : Reeve, Conch. Icon., vii, pi. 207, f. 1460 ; Pfeiffer, 

 M.H. Viv., iii, 35. H. (Thalassia) Tullia, Gray : Hector, Cat. Land 

 Moll. N.Z., 5. Nanina (Thalassia) Tullia, Gray : Nomencl. Hel. Viv., 

 46. Patula Tullia, Gray, M.N.Z.M., 11. Psyra Tullia, Gray : Hutton, 

 T.N.Z.L, xvi, 201. Charopa (Psyra) Tullia, Gray : Tryon, Man. Conch. 

 (2), ii, 211, pi. 62, f. 40. Allodiscus Tullia, Gray : Hedley and Suter, 

 P.L.S. N.S.W. (2), vii, 638. Flammulina (Allodiscus) Tullia, Gray: 

 Pilsbry, Man. Conch. (2), ix, 14, 15, pi. 3, f. 12 (protoconch) ; pi. 2, 

 f. 11, 12 (jaw and radula) : Suter, J. de Conch., xli, 251, pi. 9, f. 2, a-c. 



Shell depressed, imperforate, thin, closely ribbed, diaphanous, not 

 shining. Sculpture : Protoconch microscopically finely spirally striate ; 

 succeeding whorls with fine sharp sinuous radial riblets, about 12 per 

 millimetre ; interstices beautifully and very distinctly microscopically 

 reticulated. Colour pale yellow, faintly tessellated with rufous. Epi- 

 d'rmis thin, membranous. Spire slightly convex, about one-third 

 the height of the aperture. Pwtoconch of 1^ convex whorls. Whorls 

 5, rather convex, narrow, the last not descending, periphery sometimes 

 obscurely angled ; base rounded, impressed in the middle. Suture 

 impressed. Aperture subvertical, lunar. Peristome simple, straight, 

 sharp. Columella very short. Inner lip slightly callous, oblique and 

 arcuate, reflexed above, usually producing a shallow false perforation ; 

 a thin white smooth callosity on the convex parietal wall. 



Diameter Maj., 4-5 mm. ; min., 4mm. : height, 2mm. 



Dentition. Suter. T.N.Z.L, xxiv, 291, pi. 21, f. 18, 19. 



Jaw slightly arcuate, not tapering, with about 14 flat broad plaits 

 slightly indenting both margins. 



Radula having the formula 80x15+6+1 + 6-1-15. Central 

 tooth rectangular, somewhat longer than broad. Reflection tricuspid, 

 median cusp slender, with a short cutting-point ; side cusps rounded, 

 short, each with a minute cutting-point. Laterals asymmetrical, 

 much longer than broad ; reflection bicuspid, with a strong and long 

 mcsocone and a short ectocone. Marginals broad, the first two tri- 

 dentate, the mesodont much longer than the others, the last marginals 

 small, bidentate. 



Type in the British Museum. 



Hob. North Island : Auckland (Greenwood) ; Thames ; Ohaupo 

 (Musson) ; Mount Pirongia (T. Urquhart) ; Waimarama (A. Hamil- 

 ton) ; Forty-mile Bush (H. S.) ; Ngaputahi, Tuhoe-land (A. Hamil- 

 ton) ; Wellington (H. S.). South Island : Kenepuru (McMahon) ; 

 Nelson ; Oxford, Canterbury ; Greymouth (R. Helms) ; near Christ- 

 church (H. S.) ; Akaroa (F. Suter) ; near Lake Coleridge ; western 

 slope of Mount Cook ; Hooker Valley (H. S.) ; Albury (W. W. Smith) : 

 Queenstown (Captain Hutton). 



Var. albinus. Shell uniformly white, no colour-markings. 

 Flab. Sealy Range, near the Hermitage. Mount Cook (H. S.). 



