232 THE PEOCEEDINGS OF THE LINNEAN SOCIETY 



This fossil is a very interesting and new form, differing com- 

 pletely from every species of the Paris or Vienna basins. It is 

 very beautifnlly latticed and gracefully slender, in a way to which 

 I am sorry to say the figure does but scant justice. It is very 

 like C. cribarium, S. Wood (See Monograph of Crag MoUusca in 

 the Paleontographical Society's publications, 1848, p. 71). In 

 the diagnosis Mr. Wood says that the shell is ornamented with 

 four to five elevated transverse ridges and decussated with lines 

 of growth. The base is smooth. In our fossil the base is also 

 smooth, except for one elevated ridge near the angular edge, but 

 the spiral ridges on the whorls are crossed by distinct fine raised 

 riblets, giving rise to a very elegantly latticed pattern. The 

 canal is also very much twisted and recurved. Altogether it is a 

 very perfect representation of G. cribaHum in our Australian 

 tertiary beds. 



Cerithium apheles. Plate 20, fig. 15. 



(7. t. elongato-turrita, suhulata, tenui, sordida, parum nitente ; 

 Qjufr. 15 — 18, parum convexis, medio obsolete carinatis, et costatis, 

 varicibus inconspicuis paucis insignitis, undigue regulariter spiraliter 

 siriatis. Striis infra carinam distantibus, intersiitiis plaMatis ; 

 supra carinam, vero, crebris, inter stitiis funiculatis. Anfrac. spirce 

 angulatis et costaiis ; nucleo, 3 anfr. Icevi. Sutura lata, planata, 

 marginata. Apertura orbiculata ; labro tenui ; columella gracilis 

 contorta ; canali longo, tenui, recurve. Basi concava, striata, peri- 

 pheria lamellosa. Long. 20 — 30, lat. 6 — 8. 



This peculiar form of Cerithium, is very common at Muddy 

 Creek and at Table Cape ; but in the latter locality it reaches a 

 much larger size. It may be said to be the commonest form of 

 Cerithium and almost the commonest fossil. Its distinguishing 

 features are that it has only obsolete ribs which are scarcely per- 

 ceptible by more than a somewhat rugose surface, except on the 

 upper half of the spire ; it has occasional varices, which are not 

 very conspicuous, and the whole surface is spirally grooved. 

 There is a kind of obscure keel on the lower whorls which 

 becomes more marked on the upper ones ; below this the striae 

 are distant and rather broad, above they are close, tine, and the 



