227 
some 40 miles west of Eucla. They were of medium size, 
mature, and almost destitute of the zigzag colour-markings. 
When the trawler was in the Great Australian Bight in 1912 
several examples were taken along the 100-fathom line in 
various stages of preservation. All were inhabited by hermit 
crabs but one; from this a radula was obtained. From the 
material thus provided the following information is supplied: 
—The shell when mature may measure only 4 in. long by 
24 in. broad, or it may reach 9 in. by 4# in. One example 
is 7 in. by 44 in., proportionately much more ventricose, with 
a shorter spire, though with the same number of whorls. The 
protoconch is very conspicuous and is never absent, which is 
remarkable, since fully three-fourths of a large hemisphere 
projects. It is set obliquely, so that the nuclear spheroid has 
its flattened pole on one side. The initial point is deep blackish- 
brown, and this colour runs along the nuclear suture, and 
gradually spreads and fades out. There is no defined inner lip, 
except in one example, a micromorph, which has a detectible 
glaze spreading over the base of the body-whorl. In mature 
shells the outer lip ascends well and rapidly at the suture for 
a full inch in larger examples, and is here markedly everted, 
and the whole of the outer lip is somewhat curved out. There 
is a well-marked anterior notch } in. deep by 1 in. wide, and 
the low wide rounded varix of the notch winding round to 
the upper plait on the columella forms a low furrow, which 
in senile shells become filled up and even convex. The plaits 
are normally three, and remain unchanged in senile shells; 
but often another plait arises between the lowest two, some- 
times between the highest two, and once above all the rest. 
When senile the shell becomes very heavy, thickened especially 
on the inner side of the everted lip and along the columella. 
Colour: the typical tint is pale-yellowish, but it may be a 
rich chestnut-brown. The ornament consists typically of axial 
series of oblique lines in zigzag arrangement; these oblique 
lines may be very long, going one-third round the shell, con- 
cealing any axial disposition, or they may be short and close 
set and blotchy at their junction, so as to exaggerate it. Some- 
times they are altogether absent, leaving only the ground-tint, 
almost an albino variety, as in the two examples taken alive 
by Mr. Dannevig in 100 fathoms west of Eucla. In some 
specimens a white spiral band, starting from the aperture just 
below the suture, winds round the shell and interrupts all the 
colour-markings. The radula (pl. xvi., figs. 1, 2) from a 
living individual of 21 cm. in length measures 21 mm. by 
1 mm., and consists of a single line of seventy imbricating, 
tricuspidate, rachidian teeth only. The old teeth have their 
cusps completely worn away, and are reduced to the crescent- 
shaped bases. 
