40 



i877- Dentalium dispar Sovveiby. Braziek, Proc. Linn. Soc. N. S. Wales II, p. 58. 

 1897. Dentalium dispar Sowerby. FiLSBRY & Sharp, Man. of Conch., vol. XVII, p. 32, pi. 4, 

 figs 52—56. 



Stat. 181. Ambon. 54 Metres. Mud, sand and coral. i Spec. 



Diagnosis. Shell rather slender, the length about 9 times the greatest diameter in 

 adults; earlier third well curved, the rest of the length but slightly arcuate; much attenuated 

 toward the fine apex; rather thin, white or bluish-white, glossy and brilliant. Sculpture: four 

 angled at apex (square in section), the angles dorsal, ventral and lateral, continuing as keels 

 which rapidly become obsolete (extending two thirds the length of shell in a specimen 15 mill. 

 long, but only one third the length in one 30 mill. in length) ; each of the four primary ribs 

 bifid or trifid in summit. Betvveen these angles, throughout their extent, the surface has very 

 fine longitudinal riblets; and not far from the apex a secondary rib arises in each of the four 

 faces, and continues as far as the primary ribs. The larger moiety of the shell is polished, 

 cylindrical, wholly free from longitudinal sculpture. Growth striae fine and inconspicuous. 



Aperture slightly oblique, subcircular, the peristome thin ; anal orifice square with thin 

 walls, and without slit or notch. 

 Length 30, antero-posterior diam. of aperture 3 mill., lateral 3,2 mill. (P. & Sh.). 



Distribution. Singapore (Sowerby S. Archer) Samar, Philippines (Sowb.) China Sea. 

 Darnley I. Torres Straits 30 fms (Chevert Exp.). 



Remarks. The single specimen obtained by the Siboga has a length of 32 mill. with 

 a greatest diameter of 3,5 mill. The shell is rather transparent with many opaque bands. At a 

 distance of less than 10 mill. from the apex, the shell is smooth. There is a small wedgelike 

 notch at the apex, bordered by a slight rim, indicating the existence of a supplemental tube. 



47. Dentalhim dipsycha Pilsbry & Sharp. PI. II, figs 24, 25. 



1897. Dentalium dipsycha Pilsbry & Sharp, Man. of Conch., vol. XVII, p. 33, pi. 4, fig. 57 — 60. 

 Stat. 174. Waru bay, North coast of Ceram. 18 Metres. ]\Iud. i Spec. 



Diaenosis. Shell slender, the length about 11 times the diam., well curved, attenuated 

 toward the apex; white, nearly lusterless. Sculpture: at and near the apex square in section, 

 with four acute, narrow, projecting, longitudinal pinched-up ribs, the spaces between flat; not 

 far from the apex in each face a median thread arises, and soon equals the primary four in 

 size ; each interval then bears a tertiary thread, and here the section of the tube has become 

 circular. At about the middle of the length another set of interstitial threads appear; so that 

 at the aperture there are 32 flat, equal, low, but abruptly defined riblets, separated by flat 

 interstices of about the sanie or slightly greater width. Interstices everywhere plain, except for 

 circular growth-lines, which are moderately obvious throughout. 



Aperture rounded, somewhat compressed antero-posteriorly, the inner margin less curved; 

 hardly oblique; peristome thin. Anal orifice circular, occupying a very short tube. No slit. 

 Length 45, antero-posterior diam. of ajjerture 3,8, lateral diam. 4,1 mill. (P. «& Sn.). 



