204 GASTROPODA. [Pectinibranchia. 



Diameter, 1-3-1-6 mm. ; height, 2-2-2-8 mm. 



Animal unknown. 



Type in my collection. 



Hob. Snares, in 50 fathoms (type) ; Bounty Islands, in 50 fathoms 

 (Captain Bollons). 



Remarks. Allied to the. Australian R. devecta, Tate ( = gracilis, 

 Angas), which, however, has more numerous axial riblets. 



8. Rissoa pingue, Webster, 1906. Plate 12, fig. 8. 



Bix.soa pingue, Webster, T.N.Z.I., xxxviii, 1905 (1906), 307, pi. 38, f. 7. 



Shell very small, oval, minutely clathrate, imperforate. Sculpture : 

 Fine spiral lines, 3 on the third and 4 on the penultimate whorl ; 

 the spirals are crossed by close-set longitudinal riblets as strong as 

 the spirals, they die out on a level with the posterior angle of the 

 aperture, and the base has 3 spirals only. Colour white. Spire 

 conical, a little higher than the aperture, outlines convex. Protoconch 

 globose, glossy, of 1^ whorls. Whorls 4|, regularly increasing, slightly 

 flattened at the periphery ; base flatly convex. Suture much im- 

 pressed. Aperture oblique, oval, slightly angled above. Peristome dis- 

 continuous. Outer lip thickened externally, especially at the junction 

 with the body, behind which there is a deep groove. Columella 

 slightly oblique, arcuate. Operculum unknown. 



Diameter, 1-25 mm. ; height, 2 mm. 



Animal unknown. 



Type in the Dominion Museum. Wellington. 



Hob. Off Great Barrier Island, in 110 fathoms (type). 



Subgen. 3. ONOBA. H. and A. Adams, 1854. 



Onoba, H. & A. Ad.. G.R.M., i. 1854, 331. Type: R. striata, Montagu. 

 T urbon ilia. Leach, not of Risso. 



Shell turbiniform or somewhat elongated ; whorls convex, conspicu- 

 ously spirally striated, sometimes with short longitudinal plicae at 

 the suture ; aperture oval ; peristome continuous, thin or slightly 

 thickened. 



KEY TO SPECIES. 



A. Body-whorl with 5 broad .spirals, no axial sculpture, except growth- 



lines . . . . . . . . . . . . . . Svteri. 



B. Body- whorl with 4 spirals, and with dense axial foliations . . ioliata. 



9. Rissoa foliata, Suter, 1908. Plate 12, fig. 9. 



Rissoa foliata, Suter, P. Mai. S., viii. 28, pi. 2, fig. 23. 



Shell minute, turriculate, imperforate, solid, opaque-white, spirally 

 ribbed. Sculpture : The first 1| whorls are microscopically distantly 

 spirally striate ; the succeeding whorls have on the upper third a 

 strong spiral cord, and below it 2 smaller ones, the lower of which 

 margins the suture ; on the last whorl the whole of this sculpture 



