98 



three are relatively wide, the second and third of about the same 

 width, but wider than one ; the fourth is a slender lineation sunk 

 in the sutural canal). The first and second ligatures are broken- 

 up into blunt, straight, axial ridges, separated by about as wide 

 indented interspaces. 



Aperture oval, peristome thin. Columella slightly arched, 

 forming a blunt roundly-effuse angle at the front; thinly and 

 sparingly exsert to form an umbilical chink ; there is a slender 

 transverse plait at its summit. 



Length, 3 ; width, 1 -4 mm. 



Of six examples two are in accord with the foregoing descrip- 

 tion. A third and fourth, which are translucent horn-colored, 

 have the first and second ligatures studded with small granules; 

 whilst the fifth and sixth, also translucent, are without ornament, 

 and the spiral furrows are feebly developed and barely traceable 

 on the body-whorl. 



D'Entrecasteaux Channel, Tasmania ( W. L. May). 



Genus Pseudorissoina, Tate and May. 



Type : — P. Tasmanica, Tenison- Woods (Sty lifer). 



Apex sinistral, spire and aperture like Rissoina (e.g., R. nivea). 



The unique species was originally described as belonging to 

 Stylifer ; Tryon, who figures an authentic specimen, says of it — 

 u Is it not rather an JEulima ? " Our study of the species con- 

 firms Ten.-Woods' statement that the apex is sinistral — indeed, 

 whilst having the spire and aperture of a Rissoina, like R. nivea 

 (the shell is, however, smooth), it has the heterostrophe loop-like 

 nucleus of Eulimella. Such a combination of characters seem to 

 be unprovided for in the families Pyramidellidse or Rissoidse, 

 hence the new generic designation. Briefly, this new genus is a 

 Pyramillid with a Rissoina aperture or a Rissoinid with a 

 Pyramilloid nucleus. The higher value of the nuclear character 

 in classification induces us to place it, in Pyramidellidae, near 

 Eulimella. 



Turbonilla admiranda, nom. mutand. 



Elusa bifasciata, Ten.-Woods, P.R.S. Tasm., 1877, p. 150; 

 non Turbonilla bifasciata, A. Adams, 1861. 



T. festiva, Angas, P.Z.S., 1877, t. 5, f. 4; non Folin, 1867. 

 Victoria, Tasmania, and N.S. Wales. 



Rissoia (Apieularia) demessa, spec. nov. 

 Shell minute, strong, pale-brown. Spire-whorls four, convex, 

 ornamented with narrow rounded oblique ribs (about fourteen on 

 the penultimate), more prominent medially, and attenuated at 

 the sutures; also with spiral grooves, which are about as wide as 

 the intervening flat threads (about eight on the penultimate) ; on 



