Allodiscus.] GASTROPODA. 639 



little sinuous, 6-7 per millimetre ; interstices with very fine incre- 

 mental lines, which are crossed by indistinct fine microscopical spiral 

 striae ; the latter sculpture is also present on the protoconch. Colour 

 fulvous, with broad distinct chestnut radiate streaks on the upper 

 part of the whorls, forming anastomosing zigzag lines on the periphery 

 and base. Epidermis thin, not shining. Spire low, broadly convex, 

 about one-third the height of the aperture. Protoconch of 1|- smooth 

 convex whorls. Whorls 44, regularly increasing, convex, periphery 

 sharply rounded ; base flatly convex. Suture very distinct and well 

 impressed. Aperture oblique, lunate. Columdla oblique, a little con- 

 cave. Inner lip lightly callous, reflexed over the not much impressed 

 umbilical tract, and spreading broadly as a thin white callosity over 

 the convex parietal wall. Umbilicus completely closed in adult 

 specimens. 



Diameter Maj., 7 mm. ; min.. 6-2 mm. : height. 4 mm. (type). 



Animal unknown. 



Type in my collection. 



Hab. Poor Knights Islands (C. Cooper). 



Remark. This species stands nearest to A. (Hmoi-film*. but is dis- 

 tinguished from it by its much smaller size and the closer riblets. 



5. Allodiscus dimorphus, Pfeiffer, 1853. Plate 50, fig. 5. 



Helix dimorpha, Pfr., M.H. Viv., iii, 1853, 68 ; P.Z.S., 1852 (1854), 148 ; 

 Conch. Icon., vii, pi. 128, f. 775. H. (Charopa) dimorpha, Pfr. : Hector, 

 Cat. Land Moll. N.Z., 8 ; Nomencl. Hel. Viv., 97. Patula dimorpha, 

 Pfr., M.N.Z.M., 6. Psyra dimorpha, Pfr. : Hutton, T. N.Z.I., xvi, 201. 

 Charopa (Psyra) dimorpha, Pfr., Man. Conch. (2), ii, 211, pi. 62, f. 39. 

 Allodiscus dimorphus, Pfr. : Hedley and Suter, P.L.S. N.S.W. (2), vii, 

 638. Flammulina (Allodiscus) dimorpha, Pfr. : Suter, J. de Conch., xli, 

 250 ; Man. Conch. (2), ix, 15. 



1 depressed, imperforate, thin, radially striated, diaphanous, a 

 little shining. Sculpture : The protoconch is microscopically radially 

 wrinkle-striate, with obscure spiral lirte ; succeeding whorls rather 

 distantly radially costate, about 4 riblets per millimetre ; they are 

 subequidistant, thread-like, slightly sinuous, extending over the base ; 

 interstices with about 10 fine growth-lines, crossed by microscopic 

 very dense spiral strise. Colour pale-horny, minutely rufously tessel- 

 lated by zigzag lines, and at the suture ornamented with rufous spots. 

 Epidermis thin, membranous. Spire scarcely elevated, flatly convex, 

 about one-quarter the height of the aperture. Protoconch of If convex 

 whorls, quite flat. Whorls 4| to 5, rather convex, the last not de- 

 scending, higher than broad ; base flattish. Suture broadly impressed. 

 Aperture subvertical, lunar. Peristome simple, straight, with the basal 

 margin somewhat bent backwards. Columella short, very oblique, a 

 little arcuate. Inner lip callously reflected above, spreading broadly 

 as a thin bluish-white callosity over the convex parietal wall. The 

 free reflection of the inner lip forms a shallow false perforation. 



