GASTROPODA. [Pectinibranchia. 



KEY TO SPECIES. 



A. Body-whorl with a narrow groove on the periphery, suture 



channelled .. .. .. .. .. .. incidata. 



B. Body-whorl without spiral groove, suture not channelled. 



a. Whorls with microscopic spiral striation. 



b. Protoconch microscopically spirally striate and punc- 

 tate, suture not margined, colour purplish-red . . subfusca. 

 bb. Protoconch smooth, sometimes microscopic spirals 

 on the following whorls, suture margined, coloiir 

 white .. -. .. .. .. lampra. 



aa. Whorls without spiral striation. 



b. Shell broadly oval, conical, pink. 



c. Outlines of spire straight, height of shell with 5 



whorls 2-3 mm., uniformly pink . . . . rosect, 



cc. Outlines of spire somewhat convex, height of shell 

 with 4 whorls 1-5 mm., last whorl with pink 

 bands . . . . . . . . . . roseocincta. 



bb. Shell elongately oval, fuscous, with a pale band below 



the suture . . .... zosterophila. 



14. Rissoa incidata, Frauenfeld, 1867. Plate 12, fig. 14. 



Sabancea incidata, Frfld., " Novara" Exped.. Zool., ii. Moll., 12, pi. 2, f. 19. 

 Rissoa incidata, Frfld. : Suter. P. Mai. S., iii. 3 ; Man. Conch. (1), ix, 339. 

 pi. 63, f. 65 ; Pritchard and Gatliff, P.R.S. Vic., xiv (n.s.), 103. 



Shell minute, conoidal, thick, smooth, brownish. Sculpture con- 

 sisting only of a short spiral groove continued over the body-whorl 

 from the suture ; this, however, is sometimes obsolete. ' Colour 

 yellowish-brown. Spire conical, higher than the aperture, outlines 

 almost straight. Protoconch small, globose, smooth. Whorls 5, flat- 

 tened ; base rounded. Suture channelled. Aperture oval, slightly 

 angled above. Peristome discontinuous, much thickened inside, blunt. 

 Columella vertical, slightly arcuate, very callous. Operculum un- 

 known. 



Diameter, 0-8 mm. ; height, 1-5 mm. 



Animal unknown. 



Type in the K.K. Hof museum, Vienna. 



Hob. Te Onepoto, near Lyttelton (H. S.) ; Lyall Bay and Titahi 

 Bay (Miss Mestayer). The type is from Botany Bay, N.S.W. The 

 species is also found in Tasmania. 



15. Rissoa lampra, Suter, 1908 Plate 12, fig. 15. 

 Rissoa lampra, Suter, P. Mai. S., viii, 29, pi. 2, f. 25. 



Shell minute, ovate, imperforate, translucent, polished. Sculpture : 

 Sometimes a few microscopic distant spiral lines are present on the 

 upper whorls, but usually the surface of the shell is quite smooth. 

 Colour white. Spire conic, higher than the aperture, the outlines 

 slightly convex. Protoconch small, globose, and smooth. Whorls 5, 

 slightly convex, the last rounded, but somewhat flattened below the 

 suture ; base convex. Suture not much impressed, margined below. 

 Aperture oval, vertical, angled above. Peristome continuous, slightly 

 thickened and expanded. Columella short, arcuate. Operculum un- 

 known. 



