138 PETTERD : NEW TASMANIAN SHELLS. 



II. Rissoa approxima n. sp. Shell turbinately conoid, 

 reddish-brown, smooth, very highly polished ; whorls 

 4)4, rounded, suture impressed, apex obtuse ; aper- 

 ture ovate, labrum thin ; subumbilicate. Long i ^ 

 mill., lat. ^ mill. 



Habitat, Tamar Heads. 



Rissoa badia n. sp. Shell small, narrowly oblong, 

 smooth ; whorls 6 ; aperture small, labrum thick ; 

 apical whorls inflated. Long, i ^ mill., lat }4 mill- 

 Habitat, North Coast, and Isles in Bass's Straits. 



13. Rissoa Diemenensis n. sp. Shell turbinately-conical, 

 chocolate brown, dull; whorls 5^, convex, coarsely 

 ribbed longitudinally, emarginate at the suture, which 

 is of a paler tint than the rest of the shell ; aperture 

 almost circular, expanded, joined by a shining callous 

 deposit. Long. 2 mill., lat. i mill. 



Habitat, Table Cape and Tamar Heads. 



14. Rissoa pulchella n. sp. Shell minute, smooth, with 

 faint lines of growth, brown, ovate; whorls 4^, 

 suture fairly impressed ; subumbilicate ; aperture 

 prominent, slanting, ovate, of moderate size. Long. 

 I mill, lat. 3^ mill. 



Habitat, North Coast and Isles in Bass's Straits. 



15. Rissoa Layardi n. sp. Shell small, turbinate, white, 

 thin, subumbilicate, girded with raised spiral lines ; 

 whorls 5, rounded, suture impressed ; aperture ovate ; 

 labrum thin. Long. i| mill., lat. i mill. 



Habitat, North Coast. 



Only a small number of specimens collected. 

 May be separated by the fine spiral lines that are very 

 constant. 



J.C, iv., Jan., 1884. 



