134 



Animal. — Foot brownish-grey, muzzle black with white spots, 

 tentacles black, collar grey and creamy white. 



BZahitat. — In great profusion over the Bunda Plateau, and 

 extending to the scrubby sandhills on its east, and to the Roe 

 Plains, at the foot of the Hampton Range, in "Western Aus- 

 tralia. 



Affinities and Differences. — H. Nullarhorica has considerable 

 resemblance to BZ. Angasicma, differing from it, irrespective of 

 coloration, in its more globose form, minute umbilicus, in its 

 wrinkled surface, and longitudinally impressed lines, and in 

 the calloiis covering on the pillar. 



The ridges of growth of the shell of U. Angasiana are regu- 

 larly curved, and are interrupted by close set stria?, giving rise 

 to a granulated appearance under the lens ; but in H. 

 Nullarhorica they are wavy and varied in the degree of coarse- 

 ness, whilst the incised longitudinal lines are distant from 20 

 to 25 on the body whorl, and help to give that pitted appear- 

 ance to the shell which is observable by the unaided eye. The 

 shell is moreover remarkable for its excessively thick test, for 

 its semi-fossilized aspect, and is devoid of an epidermis. It is 

 very constant in form and colour, though in size it presents 

 great differences ; the dimensions given are those belonging to 

 a specimen of the common size. I may add, to avoid mis- 

 apprehension on the subject, that I gathered many living 

 examples. 



The specific name is adopted from that of the treeless portion 

 of the Bunda Plateau known as the Nullarbor Plain. 



Bulimtjs sinisteoesl's, iiov. spec. PL v. fig. 4. 



Shell sinistral umbilicated, oblong turretted, very thin, trans- 

 lucent, yellowish-horn coloured, showing under the lens regular 

 fine transverse stria?. Spire elongated, gradually tapering, 

 rather acute, whorls five, moderately convex, last whorl 

 equalling one-third the total length of the shell. Aperture 

 somewhat ovate ; peristome white expanded, especially the 

 columella margin ; left margin with a white tooth-like callosity 

 in the angle. 



Length, - 18 ; breadth, '06 inch. 



Animal unknown. 



BZahitat. — Under small bushes on the sandy margin of the 

 salt swamp at Peelunibie, Head of the Great Australian Bight, 

 50 examples observed. 



This shell, though it resembles B. Adelaide in a few 

 particulars, yet it cannot be regarded as a reversed form of it, 

 as its regularly increasing whorls alone prove its distinctness. 

 It may be questioned — Would it not be better to refer it to 

 Balea ? But its close affinity to Bulimus Adelaide induces me 



