or tliree strong threads ; the interspaces between the ribs and 

 adjacent to the sutures are ornamented with a few spiral 

 threads crossed bj curved lines of growth. On the anterior 

 whorls of large examples there are about eight unequal-sized 

 spiral ribs — the posterior rib on the earlier whorls has 

 developed into three prominent ribs, and one or more of the 

 intermediate threads have become conspicuous, whilst the 

 granulations of the medium rib have disappeared. 



The posterior six whorls or so have occasionally all the ribs 

 granular, thus resembling T. tSfurtli, Tenison Woods, of the 

 Tasmanian Miocene ; but at this early stage T. AldingcB does not 

 possess intermediate ribs as described for that shell. I am 

 afraid that T. Sturtii has been established on too immature 

 specimens ever to allow of satisfactory identification. 



Dimensions. — Length, 36 ; breadth, 10"5 millemetres. 



Locality and Horizon. — Argillaceous limestone and associated 

 clays at Blanche Point, Aldinga, and Kent Town bore ; also in 

 the "Turritella limestone" about x\rdrossan. 



Fissurellidsea malleata, spec. nov. 



The Eev. Tenison "Woods referred a Table Cape fossil to the 

 recent Fiss7ireUa concatenata, and I had given the same name 

 to examples collected by me from the E. Murray Cliffs and at 

 Muddy Creek ; but a more critical comparison shows that I 

 have been in error. 



The recent and fossil forms agree in shape and in the general 

 character of the sculpture ; but in the fossil the pits are of 

 smaller dimensions and more numerous ; moreover the foramen 

 is relatively larger and the median contraction is either absent 

 or only feebly shown in the larger specimens. 



The fossil species is referred to FissurellidcEa because of its- 

 affinity with the living South Australian -F/55?^r^/Z« concatenata^ 

 Crosse, .Journal de Conch., 186J?, which must be transferred to 

 that genus, because the mantle envelopes the shell, as I have 

 ascertained by repeated observation on the living animal. 



Dimensions of largest specimen. — Major and minor diameters, 

 30-0 and 20-0 ; height, 1o millimetres. 



Localiti/ and Horizon. — Gastropod bed, Eiver Murray Cliffs, 

 near Morgan, and its equivalent at Muddy Creek in Victoria ; 

 Kent Town bore, Adelaide ; probably also Table Cape, Tas- 

 mania. 



