PETTERD : NEW TASMANIAN SHELLS. I4I 



24. Cyclostrema Harriettaen. sp. Shell discoidal, openly 

 umbilicated, freely showing the whorls ; whorls 4^, 

 spire very little raised ; white, with several slightly 

 raised, rounded, spiral lines near the central portion 

 of the body whorl ; aperture rounded, diagonal, thin, 

 acute. Long. 3^^ mill., lat. i^mill. 



Habitat, North West Coast. 



A pure white species very closely allied to C. 

 Tatei Angas, from South Australia, but quite specifi- 

 cally distinct. 



25. Rissoina approxima n. sp. Shell minute, turretedly 

 elongate, sordidly white ; whorls 7, flattened at the 

 suture, numerous longitudinal rounded ribs, base 

 smooth, aperture small, roundly ovate. Long. 2^ mill., 

 lat. ^ mill. 



Habitat, North coast. 



This pretty little species may be recognized by its 

 very small size, and sculpture. It is not at all rare, 

 but like many of the more minute forms often escapes 

 notice. 



26. Trophon tumida n. sp. Shell tumidly ovate, subum- 

 bilicate, pink; whorls 5, obscurely bicarinate, longitu- 

 dinally, conspicuously plicate, plicae prominent, 

 distant, angulate and sub-foliate, transversely regularly 

 lirate, lirse rounded and crossed with fine longitudinal 

 striae ; sutures impressed ; aperture ovate, large, about 

 the length of spire, chestnut, enamelled, outer lip thin, 

 acute but thickened behind ; umbilicus small but 

 open, margined with imbricate scales almost the length 

 of the canal, which is short and straight. Long. 12 

 mill, lat 8 mill. 



Habitat, North-west coast (Miss Lodder). 



