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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 

 2 J in. broad, or it may reach 9 in. by 4| in. One example- 

 is 7 in. by 4-| 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 (pi. 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. 



