658 GASTROPODA. [Pidmonata. 



Whorls 5, rather convex, slowly increasing, the last sub- or acutely 

 angled at the periphery; base flatly convex. Suture impressed . 

 Aperture somewhat oblique, round-lunate. Peristome thin, simple. 

 Golumella short, arcuate. Inner Up very little callous, strongly re- 

 flexed above and partly hiding the narrow and deep umbilicus ; parietal 

 wall with a thin shining transparent gl;t/,< . 



Diameter Maj., 9-5 mm. ; min., 8-5 mm. : height. 7 mm. 

 Animal slender, finely wrinkled, yellowish-white. Oculiferous ten- 

 tacles long, slender, black, with 2 black longitudinal lines extending 

 over the neck, which is yellowish spotted with white. Mantle sub- 

 central, marbled with black. Foot long and narrow, with a peripodial 

 groove, rounded behind, and with a caudal gland. Length of animal, 

 about 13 mm. ; width of sole, H mm. 



Dentition. Suter, T.N.Z.I., xxiv. 291. pi. 21, f. 16. 17 ; Man. 

 Conch. (2), ix, pi. 2, f. 19, 20. 



Jaw membranaceous, horseshoe-shaped, with imbricating plaits, 

 which are very broad in the centre, narrower towards the ends ; cutting- 

 edge with a median projection. 



Radula with the formula 80x15+6+1 + 6+15. Central tooth 

 rectangular, long and narrow, reflection small, mesocone long, ecto- 

 cones obsolete. Laterals with a broader base and larger reflection, 

 the inner teeth with one cutting-point, the outer ones tricuspid, with 

 a strong mesodont. Marginals first bicuspid, then tricuspid. the 

 cutting-points sometimes coalescing. 

 Type in the British Museum. 



Hal). North Island : Tom Bowline's Bay, near North Cape (C. 

 Cooper) ; Whangaruru ; Whangaroa ; Whangarei ; Chicken Island 

 (C. Cooper) ; Helena Bay ; Mokohinau Island ; Little Barrier Island 

 (Adams) ; Rangitoto Island ; Wade ; Thames ; Auckland ; East 

 Island (Captain Bollons) ; Ruatahuna (E. Best) ; Manawatu Gorge 

 (W. W. Smith) ; Wellington ; Dannevirke ; Mauriceville (H. S.). 

 South Island : Wairoa Gorge ; Nelson ; Amuri (F. Suter) ; Kaikoura 

 (Marriner) ; Happy Valley, Canterbury (F. Suter) ; Hossack Downs 

 (E. Suter) ; Sealy Range and Hooker Valley (H. S.). 



Fossil in the Pleistocene of Petane and Matapiro ; no doubt errone- 

 ously determined as Therasia Thaisa by Hutton. 



4. Therasia Ophelia, Pfeifler, 1855. Plate 50, fig. 9. 



Helix Ophelia. Pfr., P.Z.S., 1854 (1855), 146 : M.H. Viv., iv, 29 : Reeve, 

 Conch. Icon., vii, pi. 191, f. 1345 : Cox, Mon. Austral. Land Shells, 34, 

 pi. 9, f . 4 ; pi. 17, !' 17. H. (Trochomorpha) Ophelia, Pfr. : Hector, 

 Cat. Land 'Moll. N.Z., 6. Trochomorpha Ophelia, Pfr., Nomencl. Hel. 

 Viv., 80. Helix Ophelia, Pfr. : Hutton, M.N.Z.M., 18. Therasia Ophdia. 

 Pfr. : Hutton. T.N.Z.I., xvi, 202. Charopa (Therasia) Ophelia. Pfr. : 

 Tryon, Man. Conch. (2), ii, 211, pi. 62, f. 42. Therasia Ophelia. Pfr. : 

 Hedley and Suter, P.L.S. N.S.W. (2), vii, 640. Flammulina (Therasia) 

 Ophelia, Pfr. : Suter, J. de Conch., xli, 245 : Man. Conch. (2). ix. Hi. 

 Shell turbinately depressed, narrowly umbilicated, thin, not shining, 



diaphanous. Sculpture. : ProtoeonrH microscopically faintly spirally 



