408 GASTROPODA. \Pectinibranchia. 



flatly rounded spiral ribs, one on the spire-whorls, which is mostly 

 distantly noduled ; body-whorl with 5 ribs, slightly noduled and orna- 

 mented with fine microscopic striae ; interstices narrow, deep, with 

 axial foliations ; fasciole distinct, lamellate. Colour whitish, interior 

 bright purple, outer and inner lip white. Spire conical, with an 

 acute apex, of the same height as the aperture without canal. Prnto- 

 conch depressed globular, white and smooth, of 1J whorls, the last 

 half carinated. Whorls 5, those of the spire small, the last large and 

 ventricose, depressed and flat below the suture ; base slightly con- 

 tracted above the canal. Suture superficial, margined above. Aper- 

 ture oval, subvertical, broadly angled above, narrowed below and 

 produced into a short, oblique, and open canal. Outer lip sharp, 

 thickened, crenulated by the spiral ribs, with -1 or 5 white teeth inside. 

 Columella vertical, very lightly excavated, narrowed below to a fine 

 ridge, margining the canal. Inner /// thin, widespread, extending 

 over the concave parietal wall to the outer lip. Umbilical chink very 

 narrow or covered by the lip. Operculum with the nucleus terminal. 



Diameter. 9 mm. ; height, 15 mm. (type). 



Dentition. Central tooth with 5 cusps, the median large, the 

 outer 2 a little smaller, and the intermediate 2 minute. 



Type in the Canterbury Museum, Christchurch. 



Hob. Port Waikato (t. F. Cheeseman). 



Fossil in the Pliocene. 



Remark. The information about operculum and dentition were 

 kindly supplied by Mr. W. H. Webster. 



4. Trophon patens, Hombron and Jacquinot, 1854. Plate 45, 

 fig. 15. 



Purpura patens, H. & J., Voy. P.S., v, 1854, 85, pi. 22, f. 1, 2 ; Man. Conch. (1), 

 ii, 177, pi. 54, f. 171. Polytropa patens, H. & J. : Mutton, M.N.Z.M.. 57. 

 Trophon patens, H. & J. : E. A. Smith, P. Mai. S., i, 57 ; Suter, J. Mai., 

 vii, 56 ; Index, 72. 



Shell ventricose, solid, umbilicus covered, spirally lirate to quite 

 smooth. Sculpture consisting of close and more or less numerous 

 flatly rounded spiral ribs, their number on the body-whorl varying 

 from 7 to 15 in specimens not over 35 mm. in height ; the interstices 

 narrow, very often forming linear grooves only ; very often the spirals 

 are becoming obsolete or disappear altogether ; the whole crossed by 

 oblique growth-striae ; the fasciole distinct, lamellate. Colour white, 

 cinereous, or light yellowish-brown ; aperture reddish-brown within ; 

 outer lip and columella white. Spire usually short, conical, mostly 

 lower than the aperture, but occasionally as high as the aperture 

 with canal. Protoconch with a minute nucleus, the whorls carinated 

 and minutely reticulated. Whorls 5, the last very large, very lightly 

 convex, flat or somewhat depressed below the suture ; base contracted 

 above the fasr-iole. Suture not deep. Aperture oval, angled above. 



