Webstek. — On home New Species of Shells. 277 



squamose growth-lines ; each rib ends with a flat hollow tooth 

 projecting beyond the periphery ; suture only marked by the 

 serrated periphery, as in A. heliotropium. A rounded thread runs 

 round the entire shell about one-third above the periphery. 

 The squamose base is slightly rounded, and has six rounded 

 threads between the outside edge and the columella ; the second 

 from the outside is very prominent, the fifth is somewhat so, 

 and both persist into the aperture beneath the nacre. Columella 

 white, vertical, the inside rounded and coated with a layer of 

 dull nacre ; there is a very slight umbilical depression. Animal 

 and operculum unknown. Height, 10 mm. ; breadth, 13 mm. 



Hab. Takapuna. 

 Type in my collection. 



N.B. — This shell does not resemble the young of any of our 

 Astralium. 



Rissoia vulgaris (= common), n. sp. Fig. 3. 



Shell pale-horny, imperforate, of 4J well-rounded deeply 

 sutured whorls, the sutures channelled, protoconch small, shin- 

 ing. The entire shell is longitudinally, finely, diagonally striate. 

 Aperture ovate anteriorly, lip thin, columella vertical, slightly 

 reflexed and continued on the body-whorl by a slight callous 

 line. Height, 2 mm. ; breadth, 1J mm. Animal and operculum 

 unknown. 



Hab. Waipipi. 



Type in my collection. 



Rissoia micans (= shining), n. sp. Fig. 4. 



Shell minute, imperforate, dark rich golden-brown, highly 

 polished ; whorls 4, rounded, divided by deep sutures, no sculp- 

 ture. Columella vertical, arched, dark-brown, slightly reflexed ; 

 aperture circular, not continuous, lip simple, very slightly ex- 

 panded, and semitransparent milk-white in colour. Height, 

 1£ mm. ; breadth, 1 mm. Animal and operculum unknown. 



Hab. Takapuna. 



Type in my collection. 



Rissoia zosterophila, n. sp. Fig. 5, a, b. 



Shell thin, imperforate, with brightly contrasting colours, the 

 upper half of each whorl milk-white, the lower half dark red- 

 brown ; the base is horny, thus leaving the red-brown colour as a 

 sub-peripheral band on the body-whorl ; this band forks length- 

 wise about half a turn from the aperture, on reaching the inner 

 edge of which it stops abruptly in most full-grown specimens. 

 Whorls 6i, scarcely rounded, the smooth elevated protoconch 

 taking up" two of these. Periphery bluntly angled, a similar pro- 



