216 Transactions. — Geology. 



Akt. XXV. — Description of some New Species of Pliocene 

 Mollusca from the Wanganui District, ivith Notes on 

 other Described Species. 



By R. Murdoch. 



[Read before the Wellington Philosophical Society, 12th Septevihcr, 



1899.] 



Plate XX. 



Ringicula uniplicata, Hutton. Plate XX., fig. 6. 



Hutton, Trans. N.Z. Inst., vol. xvii., p. 313; Macleay 

 Memorial Volume, p. 36. 



It seemed desirable that this minute species should be 

 figured, and for that purpose I am indebted to Captain Hutton 

 for the loan of type specimen. The following descriptive note 

 may, however, be added : Body-whorl with about eighteen 

 delicate spiral ribs, which are wider than the grooves, the 

 penultimate with about seven minute spirals ; the two apical 

 whorls smooth ; under an inch objective the whorls are seen 

 to be finely striate with growth-lines ; columella with two 

 plaits, the anterior much the stronger, curved and somewhat 

 reflexed ; a thick callous rib extends from the insertion of the 

 outer lip some distance down the parietal wall ; the outer lip 

 thickened and reflexed, a few inconspicuous denticles thereon ; 

 viewed from behind the reflexed lip is seen to project consider- 

 ably, and appears as a thick, smooth, rounded rib. 



Type, Canterbury Museum. 



Locality. — Petane. 



Actaeon minutissi ma, u. sp. Plate XX., fig. 5. 



Shell minute, ovato-elongate, shining, smooth, pellucid ; 

 whorls 4, apical whorl rounded, the others very slightly con- 

 vex, the outward curve from the impressed sutures a little 

 abrupt, giving a slightly turreted aspect ; body- whorl nearly 

 twice the length of the spire ; a single microscopic thread en- 

 circles the body- whorl at the periphery and a little above the 

 sutui'es on the tw'o succeeding whorls ; aperture ovate, slightly 

 oblique ; columella with a single posterior fold. Length, 

 1-96 mm. ; breadth, 0-89 mm. 



Type, Wanganui Museum. 



Locality. — Blue-clay cliffs, west of Wanganui Heads. 



This and other minute forms were sifted from sand and 

 blue clay by Mr. T. J. Haines. It difi'ers from other New 

 Zealand species in its minute size and lack of sculpture. 



