138 T ransactions. 
On a New Species of Epitonium. 
By A. W. B. PowELL. 
[Read before the Auckland Institute, 14th December, 1922 ; received by Editor, 28th 
December, 1922 ; issued separately, 26th May. 1924.] 
Plate 5. 
Warre collecting specimens of Epitonium jukesianum, philippinarum, and 
zelebori at Mount Maunganui, Bay of Plenty, Dr. Bucknill noticed another 
species that was quite distinct. Suter mentions in the Manual of the New 
Zealand Mollusca that a white variety of Epitonium tenellum is sometimes 
found. No doubt this species is the one referred to, but a closer examination 
reveals the presence of microscopic spiral striations and various points of 
difference from the other species of the genus. Epitonium zelebori also 
possesses spiral sculpture, but belongs to the section “ Cirsotrema Moerch," 
characterized by the distinct spiral keel, prominent spiral ribs, and denticulate 
axial ribs, so cannot be confused with this new example, which is a true 
Epitonium. 
A few weeks after the discovery of the species at Mount Maunganui 
Mr. La Roche, of Auckland, found seven specimens of the shell at Whangaroa. 
That a shell of this size had escaped notice so long, and was then found in 
two widely separated localities almost simultaneously, is remarkable, and 
serves to show that there is still much to be accomplished before the 
knowledge of our molluscan fauna nears completion. 
The author has great pleasure in uniting with the species the name of 
its discoverer. Thanks are also due to Mr. La Roche for his invaluable 
assistance. ! 
Epitonium bucknilli n. sp. 
Shell of moderate size, semitransparent, imperforate, thin and fragile. 
Sculpture consists of arcuate lamellar axial ribs, discontinuous over the 
whorls, 16 to 20 on last whorl. The type has 20 ribs on last whorl; 
interstices with microscopic spiral striations. Colour pure white. -Spire 
elevated, conic, about 2} times the height of aperture; outlines straight. 
Protoconch small, of 2 smooth convex whorls. Whorls 7, convex, a little 
separated, not shouldered ; base convex. Suture deep. Aperture oblique 
oval. Peristome continuous, thickened by an axial rib, very slightly 
expanded at base. Columella short, oblique, slightly arcuate. Inner lip 
slightly rounded with free and sharp margin. Operculum unknown. 
Diameter, 7mm.; height, 16-5 mm.; angle of spire, 30° (type). 
` Average specimen: Diameter, 5 mm. ; height, 11:5 mm. 
Animal unknown. 
Habitat: Mount Maunganui, Bay of Plenty; Taupo Bay, Whangaroa; 
Kaitoke, Great Barrier Island. 
Material: The holotype in the author's collection, Auckland. Six para- 
types were obtained at Mount Maunganui, twenty specimens at Whangaroa, 
and one at Great Barrier Island. 
