132 Transactions. 



As the Proceedings 0/ the Malacological Society of London are not always 

 readily accessible in New Zealand, I append Iredale's definition of this 

 genus : — 



" Orhitestella gen. nov. 



" I propose this name, and designate as type Cyclostrema bastowi Gatliff 

 {Proc. Roy. Soc. Vic. (n.s.), vol. xix, 1906, p. 3, pi. ii, figs. 8-10). I also 

 indicate it as representative of a new family Orbitestellidae, which is 

 composed of a series of minute marine molluscs with the following 

 characters : Shell thin, pellucid, discoidal, dextral, of few whorls and of 

 peculiar sculpture ; widely umbilicate, columella vertical, aperture never 

 variced, irregular in shape, edges thin. 



" I had hoped to describe the group, giving figures, but at present this 

 is impossible. I have species from various parts of New Zealand, the Ker- 

 madecs, Lord Howe Island, Norfolk Island, New Caledonia, Sydney Har- 

 bour (New South Wales), north coast of Tasmania, and Port Lincoln (South 

 Australia) — in fact, every austral locality from which I have received a 

 parcel of fine shell sand or fine dredgings. Commonly live shells have been 

 secured when live sand was received. All the species are very minute, and 

 I have about a dozen distinct species, divisible into two groups, and I hope 

 later to thoroughly elaborate the family with good figures."* 



Family AECHITECTONICIDAE. 

 Discohelix hedleyi Mestayer. 



With regard to this species I regret that, as in the case of Scissurella 

 regia, in my paper previously referred to the measurements of the holotype 

 were accidentally omitted. They are : Height, 0-5 mm. ; diameter, 1 mm. 



Family EPITONIIDAE. 

 Crossea cuvieriana n. sp. (Plate VIII, fig. 10.) 



Off Cuvier Island, Hauraki Gulf, N.Z. ; 38-40 fathoms. 



Shell small, turbinate, rather thin. Whorls 3, the last rather large, 

 convex. Protoconch small, smooth, glossy, about two whorls. Sculpture, 

 five spiral ribs, of which the upper two are stronger than the others ; all 

 are characterized by very fine close threads crossing them. Even under 

 a strong pocket-lens the tops of the spirals appear quite smooth, but a 

 3 in. objective on the microscope shows that the spirals are crossed by the 

 threads. The axial sculpture is formed by strong lamellae, somewhat 

 unevenly spaced, which become rather crowded on the base ; between 

 the suture and the two upper spirals the interstices are about four times 

 the width of the lamellae. The basal sculpture resembles Crossea 

 cancellata Ten. -Woods, but in that species the spirals are smooth. 

 Umbilicus very small. The umbilical rim is very strong and finely 

 crenulated like the spirals. Aperture vertical, circular, decidedly canalicu- 

 lated at the base. The outer lip is slightly channelled by the five spirals, 

 inner lip thin, sharp, only slightly reflexed towards the umbilical rim. 

 Colour white or very light brown ; dull surface. Individual specimens 

 vary somewhat in the density of the shell, the white specimens being 

 more translucent than the brown ones. 



* T. Iredalb, More Molluscan Name-changes, Proc. Malac. Soc, vol. 12, part vi, 

 p. 327, 1917. 



