406 GASTROPODA. [Peclinibranchia. 



much thickened inside ; it is generally finely crenulated, but some- 

 times almost smooth ; distinctly angled above, contracted on ap- 

 proaching the canal. Columctta vertical, somewhat excavated. Inner 

 lip thin, extending a short distance beyond the columella, and having 

 a well-defined margin ; it forms a more or less thick callous layer on 

 the concave parietal wall, and is narrowed below to a fine and sharp 

 ridge. The jasciole is well defined, lamellar. The umbilical chink is 

 mostly distinct. Opcrculum with the nucleus subapical. 



Diameter, 31 mm. ; height, 56 mm. : angle of spire, 50. Dia- 

 meter, 19 mm. ; height, 41 mm. (specimen from Wellington). Dia- 

 meter, 35 mm. ; height, 56 mm. (specimen from Lyttelton). 



Dentition (Suter, J. Mai., vii, 55, pi. 3, f. 11). The central tooth 

 transverse, with 5 cusps, of which the median and externals are much 

 larger, but all 5 are united at the base. Laterals angled and uni- 

 cuspid. 



Hob. Throughout New Zealand, in the laminarian zone, but not 

 common ; very rare in the coralline zone : Bay of Islands ; near Cuvier 

 Island, in 38 fathoms (Captain Bollons) ; Wellington Harbour (H. S.) ; 

 Lyttelton and Akaroa Harbours, in 2 to 6 fathoms (H. S.) ; Taumaki 

 Island, in 10 fathoms (Captain Bollons) ; Stewart Island (C. Traill) ; 

 near the Snares, in 50 fathoms (Captain Bollons) ; Kermadec Islands. 



Fossil in the Pliocene. 



2. Trophon rugosus, Quoy and Gaimard, 1833. Plate 45, fig. 14. 



Purpura rugosa, Q. & G., Voy. Astrol., ii, 1833, 569, pi. 38, f. 19-21. Fusus 

 Stangeri, Gray, Dieff. N.Z., 230 ; Hutton, C.M.M., 9 ; Trophon 

 Stangeri. Gray, M.N.Z.M., 48 ; T.N.Z.L, xvi, 219 ; Index, 72. Purpura 

 Quoyi, Reeve, Conch. Icon., iii, 1840, f. 71 ; not of Gray. Trophon 

 spiratum, H. and A. Adams, P.Z.S., 1863, 428 ; Hutton, M.N.Z.M., 

 49 ; Tryon, Man. Conch. (1), ii. 147, pi. 33, f. 354. Polytropa retiaria, 

 Hutton, J. de Conch., 1878, 20 ; M.N.Z.M., 57. 



Shell ovate-fusiform, usually narrowly umbilicated, solid, strongly 

 spirally ribbed and reticulated by axial plications, whorls keeled. 

 Sculpture consisting of very prominent spiral ribs on the upper whorls, 

 1 on the keel, 2 additional less-prominent ribs between the keel and 

 the suture above on the last two whorls, the upper of which margins 

 the suture ; body-whorl with 4 to 6 ribs below the keel, 4 of which 

 are stout, a finer spiral is sometimes present below the keel and 1 

 below the fourth strong spiral, followed by a very distinct fascicle 

 formed by former canals ; the spirals reticulated by subequidistant 

 much less prominent varices, the points of intersection nodulous ; 

 the whole shell ornamented with delicate axial foliations. Colour 

 greyish or yellowish-white, interior purple. Spire conical, a little 

 higher than the aperture without canal. Protoconch mostly much 

 eroded, the nucleus minute and pointed. Whorls 6 to 7, strongly 

 keeled below the middle, concave above and below the keel, the last 

 whorl high ; base flattish, somewhat contracted above the canal. 



