Trophon.l GASTROPODA. 405 



KEY TO SUBGENERA. 



A. Shell with a basal fascicle and umbilical chink. 



a. Surface with lamelliforrn varices . . . . . . TRornox, s. str. 



b. Surface without lamelliform varices, spiral sculpture 



predominating ; outer lip with a tubercle near the 



canal . . . . . . XANTHOCHORUS. 



c. Surface axially costate and spirally lirate . . . . KALYDON. 



B. Shell with a not prominent basal fascicle, no umbilical 



fissure, and very numerous axial lamella? . . . . TROPHONOPSIS. 



Subgen. 1. TROPHON, s. str. 



Shell broadly ovate, rounded or strongly shouldered, with numerous 

 sharp laminated varices, the interstices smooth or spirally ribbed ; 

 spire elevated ; canal short, open, nearly straight ; aperture rounded ; 

 outer lip simple : umbilicus usually open, with a prominent fascicle 

 on the outer side. 



KEY TO SPECIES. 



A. Shoulder flat, nearly horizontal, its keel very little below the 



suture . . . . . . . . umbiyuus. 



B. Shoulder sloping, its keel at or below the middle of the spire- 



whorls . . . . . . . . rugosus. 



I. Trophon ambiguus, Philippi, 1844. Plate 45, tig. 13. 



Fusus umbiyuus, Phil., Abbild. & Beschr. neuer Conch., Fusus, 1844, pi. i. 

 f. 2 ; Voy. P.S., 109, pi. 25, f. 13, 14. Trophon ambiguus, Phil., Man. 

 Conch. (1), ii, pi. 33, f. 365 ; M.N.Z.M., 48 ; T.N.Z.I., xvi, 219. Fusus 

 cretaceus, Reeve, Conch. Icon., iv. 1847, f. 48 ; Man. Conch. (1), ii, pi. 33, 

 f. 3(53. Vitularia Candida, H. and A. Adams, P.Z.S., 1863, 430. Mure>- 

 (Vitularia) Candida, H. and A. Adams, Man. Conch. (1), ii, 133. 

 M. lyratus, Lam. : Button, C.M.M., 7 ; not of Lamarck. Fusus varius, 

 Lam. : Hutton, C.M.M., 9 ; not of Lamarck. 



Shell fusiform, not very thick, usually with an umbilical chink, 

 turriculate, reticulated by spiral and axial ribs. Sculpture consisting 

 of 2 spiral ridges on the spire- whorls, the upper of which is on the 

 carina of the whorls ; interstices with an occasional finer ridge ; body- 

 whorl with numerous unequal spirals, some of which are usually more 

 prominent than the others ; a distinct fasciole along the canal ; the 

 axial sculpture formed by subequal sharp varices on the spire-whorls, 

 very inequidistant and often almost obsolete on the body-whorl ; the 

 points of intersection, especially on the carina of the whorls, nodulous, 

 or produced into short hollow spines. Colour white or yellowish : 

 inside white, greenish, or light brown. Spire conical, shorter than 

 the aperture with canal. Protoconch consisting of 2J convex and 

 smooth whorls, the nucleus minute and rounded. Whorls 1 to 8. 

 with A broad, flat, and but slightly sloping shoulder, lightly convex 

 below it ; base contracted towards the canal. Suture not much im- 

 pressed. Aperture ovate, broadly angled above, produced below into 

 a moderately long and open canal, which is recurved and bent to the 

 left. Outer lip usually thin and sharp, but in old specimens it is often 



