362 GASTROPODA. [Pectinibranchia. 



ally very faintly mottled with white ; aperture light brown, inside. 

 Spire short, conical ; apex blunt, height about half that of the aper- 

 ture ; outlines lightly convex. Protoconch small, papillate, of 2 smooth 

 whorls. Whorls 4^ to 5, the last very high, faintly convex : base 

 very little contracted. Suture lightly impressed. Aperture oblique, 

 narrow, angled above, not contracted below, slightly notched. Outer 

 Up uniformly moderately curved, sharp, slightly thickened inside. 

 Columella subvertical, with 4 oblique plaits, equally spaced, slightly 

 decreasing in size towards the base. Inner Up narrow, sharply bounded 

 on the outside, forming a thin glaze on the slightly arcuate parietal 

 wall. 



Diameter, 2-6 mm. ; height, 5-4 mm. 



Animal unknown. 



Type in the Dominion Museum, Wellington. 



//a&.^Whangarei Heads, dredged in shallow water, type (C. 

 Cooper) ; near Little Barrier Island, in 20 fathoms (R. H. Shake- 

 spear). 



Remark. The absence of regular axial costse on the body- whorl, 

 and a canal, induce me to class this species under Mitra. 



Genus 2. VEXILLUM, Bolten, 1798. 



Vexillum, Bolten, Mus. Bolten. (2), 1798, 138. First species : Mitra 

 plicaria, Lam. Tunis, Montfort, 1810 ; not of Bolten, 1798. !'/- 

 pecula, Blainville, 1824. Tiara, Swainson, 1840. Turricula (Klein). 

 Fischer, 1884 ; not Vexilla, Swainson, 1840. 



Animal similar to that of Mitra. Radula triserial ; the central 

 tooth transverse, the upper margin slightly concave, with numero 

 sharp denticles on the lower margin ; lateral teeth simple, with one 

 cutting-point, elongate and curved. 



Shell elongate, turreted, axially plicately fibbed ; spire acumi- 

 nated ; aperture narrow, with a more or less recurved canal at the 

 base ; outer lip usually internally striated ; columella with 4 but 

 slightly oblique plaits. The protoconch is papillate, paucispiral. 



This genus is exclusively tropical and subtropical in distribution, 

 and it is abundantly represented in central Polynesia. 



Fossil in the Tertiary. 



KEY TO SPECIES. 



A. Columella with 3 plaits . . . . . . . . Waitei. 



B. Columella with 4 plaits. 



<i. Height of spire less than that of aperture ; spiral lira? 



distinct only below the suture and on the base . . obncururn . 

 mi. Height of spire about equal that of aperture. 

 li. Suture margined. 



c. Outer lip much contracted at the base ; 

 whorls with about 14 large nodules on 

 the angle of the shoulder . . . . marginatum. 



<<-. Outer lip but little contracted at the base ; 

 axial riblets 14-15, prominent ; inti-i 

 slices spirally lirate . . . . pseudomarginatum. 



