Monodonta.] GASTROPODA. 121 



9. Monodonta subrostrata, Gray, 1835. Plate 38, fig. 11. 



Monodonta subrostrata. Gray: Yate, N.Z., 308; Man. Couch. (1). xi, 101, 

 pi. 19, f. 89, 90 ; Suter, P. Mai. S.. ii, 266. TrocJiocochlea subrostrata, 

 Gray : Hutton, M.N.Z.M., 96. 



Shell conical, suborbicular, solid, imperforate. Sculpture consist- 

 ing of distant subnodulous spiral ridges, 3 to 6 on the penultimate 

 whorl, interstices without spiral sculpture, the whole crossed by oblique 

 fine and close growth-lines ; base with about 6 concentric close ridges. 

 Colour yellowish, with undulating longitudinal purple lines. Epi- 

 dermis thin, mostly rubbed off. Spire conoidal to conical, acute. 

 Protoconch small, conic, acute, smooth, mostly eroded. Whorls 5, 

 rapidly increasing, convex, the last slightly angled at the periphery ; 

 base convex. Suture well impressed, margined below. Aperture ob- 

 lique, silvery, distantly lirate. Outer lip convex, sharp, edged with 

 yellowy and often dotted with black ; then a narrow band of opaque 

 white. Columella oblique, opaque white, nearly straight, broad, and 

 smooth, with an indistinct tooth below, mostly, however, obsolete. 

 Umbilical tract rather broad, greyish or yellowish-grey on its outer 

 lower margin ; a pearly band extends from the lower lip up to near 

 the centre of the umbilical tract. 



Diameter, 13-15 mm. ; height, 11-14 mm. Diameter, 23mm.; 

 height, 24 mm. (my largest specimen). 



Dentition. Hutton, T.N.Z.I., xv, 126, pi. 15, f. G. 



Type in the British Museum. 



Hob. Northern part of the North Island, as far south as Tauranga. 

 Abundant on Zostera beds and on rocks. 



Sect. 3. CHLORODILOMA, Pilsbry, 1889. 



Cldorodiloma. Pilsbry, Alan. Conch. (1). xi. 10, 110. Type: M. crinita, Phil. 

 Latona, Hutton, P.L.S. N.S.W.. ix, 368 ; not of Schumacher, 1817. 



Shell like Diloma, but rather more conical, less nacreous ; colora- 

 tion variegated, consisting of fine lines of dark on a lighter ground ; 

 columella generally green ; umbilicus perforate or subperforate. 



Australasia. 



10. Monodonta crinita, Philippi, 1848. Plate 38, fig. 12. 



Trochus crinit-us, Phil., Zeitschr. f. Mai., 1848, 103. Monodonta crinita. 

 Phil., Conch. Cab.. 235, pi. 35. f. 9; Man. Conch. (1), xi, 111, pi. 22, 

 f. 4144; Suter, P. Mai. S.. ii. 267. TrocJiocochlea mimetica, Hiitton, J. 

 de Conch., 1878, 32. 



Shell globose-conic, narrowly perforate, solid. Sculpture consist- 

 ing of shallow spiral grooves, about 5 on the penultimate whorl, 

 sometimes distinctly spirally ridged ; about 7 grooves on the base, 

 getting much closer on approaching the umbilicus ; the whole crossed 

 by very fine and close growth-lines. Colour light cinereous, longitu- 



