87 

 Washed up. — Aldinga Bay, St. Vincent's Gulf, ten examples (Tate). 

 5. — Marginella dentictjlata (new species). 



Shell shining white, pear-shaped, contracted in front, spire 

 immersed ; columella quadriplicate, outer lip thickened and minutely 

 denticulated. Length, "08 ; breadth, "06 inch. 



Its pyriform shape separates it from M. pisum and M. cymbalum, 

 but it has more agreement in this particular with the Bornean M. dens 

 (Reeve); its denticulated outer lip and strong columella .plaits separate it 

 from all. 



Washed up. — Wauraltie, west coast of Spencer's Gulf, three 

 examples (Tate). 



6. — Marginella tridentata (new species). 



Shell elongately conical, yellowish white, shining ; spire some- 

 what exserted ; last whorl rather swollen round the upper part, 

 attenuated in front ; lip broadly thickened, opaque, moderately inflected 

 in the middle region, flexuous, minutely denticulated on the inner edge . 

 columella with three strong plaits. Length "25, breadth "15 inch. 



Washed up. — Aldinga Bay, St. Vincent's Gulf, one example 

 (Tate). 



I do not hesitate to found a new species upon the unique specimen 

 before me, because it presents a combination of characters — a triplicate 

 columella, denticulated lip, with a narrow conical shape, not presented by 

 any known form. Its nearest ally is M. sordida (Reeve), from which it 

 differs in being proportionately a little broader, and in having a denti- 

 culated outer lip. M. Tasmanica is the only other Australian species 

 with a triplicate columella, but its shape is widely different from the 

 present species. 



7. — Marginella albida (new species). 



Shell semi-transparent, whitish, oblong-cylindrical, surface marked 

 with regular striae of growth ; spire very short, apex obtuse ; base 

 rounded, slightly attenuated ; aperture narrow, widening to the front ; 

 columella a little arcuate anteriorly with five plaits, the anterior two of 

 which are thick; outer lip thickened, flatly variced behind, and finely 

 dentate on the inner edge with about twenty teeth. Length 2, breadth 

 •1 inch. 



This species may be characterised as a diminutive, white, Hyalina 

 pallida, Linne, with a five-plaited columella. Only two other forms of 



