820 SCAPHOPODA. [Dentalivm. 



Type in the British Museum ; of D. pacificum, in the Dominion 

 Museum, Wellington. 



Hob. Off Great Barrier Island, in 110 fathoms. 



Subgen. 3. L^VIDENTALIUM (Cossmann), Pilsbry and Sharp, 1897. 



Lcevidentalium, Cossmann, Ann. Soc. Roy. Malac. Belgique, xxiii, 1888, 9 ; 

 Pilsbry and Sharp, Man. Conch. (1), xvii, 1897, 97. Type : Dentalium 

 incertum, Desh. 



Shell of moderate or large size, smooth, with growth-lines only, 

 circular or slightly oval in section ; apex simple (typically), or with a 

 short notch on the convex side. 



KEY TO SrECiES. 



A. Apex without a notch ; length about 9 times the diameter . . ecostatum. 



B. Apex with a narrow fissure ; length about 6| times the diameter diarrhox. 



5. Dentalium diarrhox, Watson, 1879. Plate 32, fig. 5. 



Dentalium diarrhox, Watson, J.L.S., xiv, 1879, 511 ; Chall. Rep., xv, 4, 

 pi. 1, f. 5 ; Man. Conch. (1), xvii, 109, pi. 3, f. 36-38. 



Shell white (chalky), but porcellanous beneath the surface, rather 

 straight, with a considerable bend near the apex ; of rather rapid 

 expansion from a very fine apex. Sculpture: The whole surface is 

 faintly marked with scarcely impressed longitudinal lines of very 

 equal interval (about 0-0055 in. apart) ; transversely it is very faintly 

 scratched all over by very slight lines, which run elliptically round the 

 shell. The apex has a very narrow, slightly ragged fissure, about 

 0-027 in. long, which lies unsymmetrically on the convex curve. 



Length, 17-5 mm. ; breadth, 2-25 mm. 



Animal. Mantle white, body pale yellow. Captacula many, fine, 

 long, and equal, with small ovoid points. Foot and collar those of a 

 true Dentalium. (Watson.) 



Type in the British Museum. 



Hab." Challenger " Station 169, north-east from New Zealand, 

 in 700 fathoms. 



6. Dentalium ecostatum, T. W. Kirk, 1880. Plate 49, fig. 15. 



Dentalium ecostatum, T. W. Kirk., T.N.Z.L, xii, 1879 (1880), 306 ; A.M.N.H. 

 (5), vi, 1880, 15 ; Plioc. M., 74, pi. 8, f. 79 ; Man. Conch. (1), xvii, 102, 

 pi. 18, f. 13. 



Shell rather small, slightly curved, smooth and polished, very 

 gradually tapering. Sculpture consisting of faint and distant growth- 

 lines only. Colour white. Apex circular, the lip solid, rounded. 

 Aperture also circular, the lip thin and sharp. 



Length, 15mm.; breadth at anterior end, 1-75 mm. (type). 

 Length, 17mm.; posterior diameter, 2mm.; anterior diameter, 

 3'5 mm. (Pliocene specimen). 



