Allodiscus.] GASTROPODA. 645 



striated ; succeeding whorls with very fine, close, somewhat fiexuous 

 radial riblets, about 25 per millimetre ; the insterstices microscopically 

 reticulated by growth and spiral lines. Colour pale yellow with zigzag 

 streaks of rufous. Epidermis thin and glossy. Spire perfectly flat. 

 Protoconch of 1J convex whorls, flat. Whorls 4, the first three slowly 

 the last more rapidly increasing, rounded, periphery convex ; base 

 rounded, impressed in the centre. Suture impressed. Aperture ob- 

 lique, lunar. Peristome straight, acute, margins very little converg- 

 ing. Columella very short. Inner lip oblique, very little reflexed 

 above. Perforation very narrow, deep, perfectly open. 



Diameter Maj., 2-25 mm. ; min., 2 mm. : height, 1-25 mm. 



Jaw horseshoe-shaped, composed of about 28 vertical narrow 

 plaits, indenting both margins. 



Radula with the formula, 11 + 4+ 1 + 4+ 11. Central tooth tri- 

 cuspid, with 3 cutting-points, the median extending to the posterior 

 end of the base. Laterals tricuspid, the endodont rudimentary. 

 Marginals broad, with a tridentate cutting-point, and sometimes with 

 an outer small denticle. 



Type in my collection. 



Hab. Mount Somers (W. W. Smith). 



12. Allodiscus tholoides, Suter, 1907. Plate 11, fig. 8. 



Flammulina (Allodiscus) tholoides, Sut., P. Mai. S.. vii, 1907, 238, pi. 22, 

 f. 8. 



Shell small, depressed turbinate, imperforate, cost-ate, thin, not 

 shining. Sculpture consisting of sharp, almost straight, and sub- 

 equidistant radial riblets, 8 to 9 per millimeter, extending over the 

 base ; insterstices with very fine growth-hues and obsolete micro- 

 scopical spiral striae. Colour fulvous, with light-brown zigzag bands. 

 Epidermis thin, not shining. Spire broadly dome-like, very little 

 more than half the height of the aperture. Protoconch of 1^ smooth 

 and convex whorls. Whorls 5, slowly and regularly increasing, convex, 

 but slightly flattened above ; base convex. Suture well impressed. 

 Aperture a little oblique, lunar. Peristome thin and straight. Colu- 

 mella short, arcuate. Inner lip slightly callous, and deflexed over the 

 umbilical region, which is but little immersed ; a thin callus on the 

 parietal wall unites the distant margins. Perforation almost com- 

 pletely sealed up. 



Diameter Maj., 4-5 mm. ; min., 3-8 mm. : height, 3-2 mm. 



Animal unknown. 



Type in my collection. 



Hab. Cape Te Reinga (C. Cooper) ; Whangaroa. 



Remarks. The globular form and the distant almost straight 

 riblets distinguish this species from the allied A. Tullia, A. venulatus, 

 and .4. rusticus. 



