Trophon.} GASTROPODA. 407 



Suture superficial, uneven. Aperture ovate, subvertical. slightly 

 channelled above, produced below into a short and open canal, which 

 is mostly recurved and turned to the left ; the length of the canal 

 is very variable. Outer lip sharp, angled by the spiral sculpture, 

 white, toothed within. Columella vertical and straight, lightly ex- 

 cavated towards the parietal wall. Inner lip extending a short dis- 

 tance beyond the columella, with a sharp and well-defined margin, 

 spreading as a thin and white callus over the parietal wall, joining the 

 outer lip ; narrowed below to a fine edge, and forming the inner margin 

 of the canal. Umbilical chink distinct, of variable depth. Operculum 

 with the nucleus subapical. 



Diameter, 18mm.; height, 31-5 mm. (type). Diameter. 19mm.; 

 height, 34mm. (large specimen). 



Animal having an oval foot, a little broadened in front ; tentacles 

 large, conic, terminating in a sharp point, eyes near their extremities ; 

 they are whitish, and the short siphon is of the same colour. The sole 

 of the foot is yellowish-white, the margins light brown ; sides of foot 

 greenish with yellowish-white spots. 



Dentition (Button, T.N.Z.I., xv, 121, pi. 13. f. Q). Central tooth 

 with 5 narrow, pointed, separated denticles, the external and median 

 subequal, the intermediate two much smaller. 



Type in the Mus. Hist. Nat., Paris. 



Hob. From the Bay of Islands to Tauranga. on rocky ground 

 between tide-marks. 



Fossil in the Pliocene. 



Subgen. 2. XANTHOCHORUS, P. Fischer. 1884. 



Xanthochorus, P. Fischer, Man. de Conch., 639. Type : Trophon xantho- 

 stoma, Brod. 



Shell ventricose, with a short spire, devoid of varices, the spiral 

 sculpture predominating ; aperture oval, with a short and open canal 

 below ; outer lip sharp, toothed inside, with a more prominent tooth 

 or tubercle close to the canal ; fasciole not very prominent ; um- 

 bilicus generally covered by the inner lip. Operculum with the 

 nucleus anterior. 



KEY TO SPECIES. 



A. Spire-whorls with 1, body-whorl with 5 slightly nodulous cinguli Cheesemani. 



B. Shell smooth or spire-whorls with 3 and body-whorl with 7-15 



cinguli, crossed by growth-lines ; interstices mostly linear . . patens. 



C. Spire-whorls with 2-3, body-whorl with 7 cinguli, the Interstices 



nearly as broad as the ribs ; with imbricating axial foliations squamata. 



3. Trophon Cheesemani, Hutton, 1882. Plate 46, fig. 15. 



Polytropa Cheesemani, Hutt., N.Z.J.S., i, 1882, 69 ; T.N.Z.I., xv, 131. 

 Trophon Cheesemani, Hutt., I.e., xvi, 220 ; Index, 72. Urosalpinx 

 Cheesemani, Hutt. : Cossmann, Ess. Pal. Comp., v, 50. 



Shell small, ovate - fusiform, sometimes with a narrow umbilical 

 chink, solid, whitish, spirally ribbed. Sculpture consisting of broad 



