South Australian Shells. 
S.A. NAT., VOL. XIV. 
August 31st. 1933. 
142. 
cent, 15-22 fathoms, greatest length 22.5 mm. (Type locality — 
Katow, New Guinea, 8 fathoms, sandy mud and coral). Brazier 
in the definition of his species writes 'interstices with minute 
lengthened striae.” If the specimens of D. intercalatum Gould, 
from South Australia are examined under a lens when their larger 
end is towards the light they will show their transverse accre- 
mental striae very plainly, but when tlfey lie with their side to- 
ward the light these are quite indistinct, and fine axial striae are 
visible. The relative validity of these axial and accermental 
striae varies in different examples. They are seen in our speci- 
mens labelled D. katowense (Verco). 
D. thetidis Hedley 1903. “The Thetis Dentalium.” Rather 
I thin, tapering, very little curved; white; longitudinal ribs seven, 
I the whole length, those on concave side stronger and wider apart 
j than the others; each Interspace grooved by a dozen fine, even 
striae, faintly crossed by growth lines; towards tlie aperture one 
or two interstitial riblets arise; posterior orifice simple. Length 
8, diam. of aperture 1 mm. Dredged — Gulf St. \hncent 6-22 
fathoms, Cape Jaffa 130-300 fathoms. (IVpe locality — 63-75 
fathoms off Port Kembla N.S.W.). A South Australian .speci- 
men measures 20 x 2.25 mm. “In the two fresh specimens 
from 130 fathoms, close to the posterior end, in the 
furrow on each side next to the central furrenv on tlie 
convex surface, are four minute holes in an axial line, 
d'hese are probably only accidental. I'liey may be bore-hoies of 
predaceous molluscs. Still it is a curious coincidence T*' find 
them in two specimens in identically the same position; and the 
coincidence is more striking since they occur only in these two 
instances, among several hundred Dnitaliiim shells. These are 
often bored, but generally only in one or tvo holes and -n otlior 
parts of the shell. However it would be perilous to construct 
an<jther species to include these two examples, which in al! other 
respects resemble the rest under this name.” Verco (Trans. Roy. 
Sue. of S.Aus. vol. 35. 1911. p.205). 
D. bednalli Pilsbry & Sharp 1898. “BcdnalFs Dentalium.” 
Shell soiled or Isabella-whitish, moderately curved, the curvature 
posterior; longitudinal rounded ribs, seven, strong, separated 
by deeply concave and decidcly wider intervals; passing anter- 
iorly the ribs become lowxr and wider, and lend to split by the 
appearance of progressively deepening sulci on their side slopes, 
so that at the ap'jerture there are about ten very low ribs of un- 
equal prominence, besides some incipient ones; intervals .shallow 
and narrower than the ribs: growth striae fine and rather incon- 
spicuous throughout, no longitudinal striation; aperture subcir- 
cular, retaining a slightly hexagonal form, as long as wide; apex 
rather large, orifice small, oval, longer than wide, with thick walls; 
