CERiTHrcrsi. 223 



they form large dentate tubercles, the ornament towards the close 

 of that stage being typically fusoid. Then a revolution was 

 effected by the commencement of the deposition of a thick coating 

 of enamel, all ornament being covered up, the posterior prolongation 

 of the enamel hiding the suture, and being flattened and fixed to 

 the preceding whorl ; with growth, the callosity becomes broadly 

 and deeply canaliculate, a feature which continues to the ephebic 

 stage. The body-whorl of the adult is entirely covered with 

 enamel, and it would appear that the large peripheral tubercles 

 are no longer developed, as they are not traceable through the 

 enamel, which is sinuously corrugated by growth-lines and bears 

 a few spiral threads, in which last-mentioned feature we seem to 

 see a recurrence to a former state. The callous enamel spreads 

 over the whole of the body-whorl and the anterior half of the 

 penultimate whorl, in the adult. Columella thickly covered ; 

 outer margin sinuous. 



Bimensmis. — Length 38 mm.; breadth 28 mm. 



Form, and Loc. — Miocene : Victoria. 



G. 4293. Two examples of the adult ; from Muddy Creek. 



Presented by John Bennant, Esq. 



G. 4783. Specimen of the senile stage, having a more elevated 

 spire and corrugated callosity than the typical form ; from Lake 

 Tyers, Gippsland. Presented by the Rev. J. S. IT. Payee. 



G. 5530. Example having a much elevated spire ; from Muddy 

 Creek. Purchased. 



Family CERITHIID^. 



Genus CERITHIXJM, Bruguiere. 



[Eney. Meth. Yers. t. i. pt. 2, 1792, p. 467.] 



Sliell imperforate, turriculate ; whorls numerous, the last always 

 shorter than the spire ; aperture oblong, ovate, prolonged into 

 a short posterior canal ; anterior canal short, oblique ; columella 

 concave. In typical species a dentiform tubercle is developed on 

 the inner margin in the vicinity of the posterior canal, the outer 

 margin is dilated in front and the whorls are Taricose. 



