S.A, NAT., VOL. XIV. 
August 31st, 1933. By Bernard C. Cotton and F. K. Godfrey. 1-13. 
D. zelandicum Sowerby 1860 (= D. pacificum Hutton 
1873). “The New Zealand Dentalium.” Large, slightly arcu- 
ate. rather slowly tapering, with numerous unequal ribs, apex 
mostly w'ith a slit; white, banded with pale grey and tawny; 
longitudinal ribs of unequal strength, narrow, scarcely raised, 
eighteen to twenty at posterior end, thirty to forty-five at an- 
terior extremity, about twenty of which being stronger than the 
others; ribs crossed by distinct, dense, oblique growth lines; 
posterior orifice narrow, circular, sometimes with a simple, nar- 
row, ventral fissure about 4 mm. long; aperture oblique, dorsal 
lip somewhat advancing, circular; peristome thin, sharp. Length 
57. diam. 8 mm. Dredged — Cape Jaffa, also Beachport, 110-200 
fathoms. (Ih'^e locality — New Zealand). 7’he smaller ribs arise 
by Intercalation. The fissure is not alwat's present. 
D. lubricatum Sowerby I860. PL 1, hgs. 4 and 4a. “The 
Slippery !3entalium.’’ Elongate, lightly curved, polished, sub- 
pellucid, v^'hite; slightly slit, gradual!}' increasing. Length 36.5, 
greatest dlam. 3.25 mm. Dredged Beadiport, Cape Borda, Cape 
Jaffa, Neptune Islands, 40-150 fathoms. Also Western y\ustra- 
lla — Hopetoun, 35 fathoms, (d'ype locality — off Port Jackson 
Heads, 45 fathoms, hard sand bottom j Brazier |). With refer- 
ence to the slit, Soutli Australian examples show that in the very 
early stage of growth there is no slit, but a central posterior a^'er- 
ture; length of slit may vary from a mere notch to a fissure of 
8 mm. The slit is alwavs on the convex or ventral aspect. In 
some specimens the dorsal part near the posterior end is spotted 
or blotched with opaque white. Rarel}', specimens show the 
extreme posterior end, which is an elliptical bulb with a very 
sliort slightly-contracting round tubular posterior prolongation 
set somewhat obliquely to the axis of the bulb and directed to- 
ward the convex side of the shell. Opaque transverse rings ap- 
pear in the first 1.5 mm. of the shell. 
D. quadricostatum Brazier 1877. “The Four-ribbed [9en- 
talium.'’ \'ery slightl}' arched, white; four angled, keel or rib at 
cadi angle, rounded, finely serrated, interstices flat, marked with 
transverse lines; apex perforated, perforation entire; aperture 
angled. Length 16, diam. base 2 mm. Beadiport, 110 fathoms. 
(Type localitv' — Princess Charlotte Bay, North-east Australia, 13 
fathoms). If this species Is laid upon its side it forms a true 
square; when resting with the arched part of the apex down, 
it forms four angles, with a serrated rib on each angle. 
D. virgula Hedley 1903. Virgula, a little twig, refers to 
the supplementary tube at the narrow end. Shell small, a little 
curved, slightly tapering, slender in section, circular, polished, 
