289 



Triphora cana, n. sp. PI. xxiii., figs. 2, 3, and 4. 



Shell sinistral, solid, of 12 whorls, elongate-conical. Pro- 

 toconch slightly mamillate, of two whorls ; the second the 

 larger, convex, with sigmoid axial bars, 16 in a whorl. Spire- 

 whorls, the first with one nodulous carina, the second with 

 two, the third with three, the last arising between the other 

 two. Whorls sloping, the last three subconvex. Sutural 

 space distinct, with a supra-sutural thread in the last six 

 spaces, remaining nearly smooth. Tubercles close, about 18 

 in the penultimate, joined transversely and axially (obliquely 

 forwards) by stout bars which lattice the surface. Aperture 

 roundly rhomboidal, scarcely pinched behind. Outer lip 

 slightly retrocurrent towards the suture; basal lip in con- 

 tact with the erect, solid inner lip, and crossing the colum- 

 ella, where it closes in the short recurved notched, otherwise 

 open canal. Base flatly convex, bounded by the nearly 

 smooth peripheral lira, with a second smooth basal lira and 

 a third encircling the base of the canal. The protoconch and 

 first four spire- whorls are white, the rest light-brown. 



Dim. — Length, 71 mm.; breadth, 2'1 mm. 



Locality. — Type, Gulf St. Vincent, depth unrecorded, 

 with 15 good and 34 moderate examples; 35 fathoms, St. 

 Francis Island, 1 good ; 40 fathoms off Beachport, 1 good and 

 1 poor ; 55 fathoms off Cape Borda, 3 good and 5 poor ; 62 

 fathoms off Cape Borda, 1 moderate and 3 poor; 110 fathoms 

 off Beachport, 2 moderate ; St. Francis Island beach, 5 good, 

 1 poor. 



The species varies a great deal — 



1. In colour. The first six whorls may be white, and 

 all the rest a blackish-brown. The first three whorls (includ- 

 ing the protoconch) may be dark-brown, and all the rest 

 light-brown, with no white whorls. The three apical whorls 

 may be brown, the next three white, and the rest brown, so 

 connecting the previous shell with the type. The three apical 

 whorls may be brown, and the seven remaining whorls quite 

 white. The infra-sutural pearl row in the coloured portion 

 may be dark-purple or barely tinted, the others brown, or 

 the highest and lowest row may be purple and the central 

 brown. 



2. In shape. In most examples, though not in the type, 

 the posterior pearl row becomes larger than the others, the 

 pearls being greater, and consequently closer, and are some- 

 what axially elongate. When this is marked the whorl may 

 be wider below the suture than above it, so as to give a more 

 or less gradate appearance to the whorls. 



