218 KECOKDS UF THE AUSTRALIAN MUSEUM 



eleven remaining whorls. Sculpture : the adult sliell commences 

 with simple ribs springing fi'om the surface above and below and 

 projecting at the periphery. The gradual appearance of spiral 

 sculpture depresses the ribs in the middle and elevates them above 

 and below in angular tubei'cles. Finally the ribs break up into 

 bead rows, the last whorl having a smooth central belt through 

 which runs a spiral thread, on either side lie first a large and then 

 a small bead row, containing about nineteen grains to a whorl ; 

 no varix is present. The suture is impressed and sinuous. Pro- 

 tococh sharply differentiated by substance, colour and sculpture, 

 of four whorls with a double keel and delicate radial riblets, 

 tei'minating in a deep bay above a long and nai-row lobe. The 

 concave base meets the periphery at a sharp angle and is orna- 

 mented by a few shallow, wide spaced concentric grooves. 

 Aperture oblique, subquadrate ; lip sharp, simple, the short canal 

 is merely a deep sinus. Length 1 1 mm. ; breadth 3 mm. 



A few dead shells. 



After Bittium granarimn, the novelty is one of the largest 

 Australian members of the genus. The presence of a sinusigera 

 protoconch is of interest, but we have not sufficient data to now 

 discuss its teleolo";ical significance. 



Cerithiopsis cacumixatus, sp. nov. 



(Plate xxxvii., fig. 4). 



Our broken specimens, though exhibiting features sufficient to 

 separate them from known species, do not supply the material for 

 a complete description. Shell very long, slender and gradually 

 tapering to an inflated two-whorled protoconch, each whorl o^er- 

 hanging its successor pagoda-wise. Colour grey. Whorls at 

 least nineteen. Sculpture : each whorl carries about thirteen 

 longitudinal folds which taper upwards and do not continue from 

 whorl to whorl. Three spiral belts and intervening shallow 

 furrows of corresponding width develop beads on the radials. 

 The lowest chain of beads is the most prominent, and those above 

 diminish in succession. Beneath the largest bead row is a narrow 

 revolving double thread. The beads are more polished than the 

 interstices. Towards the summit the spiral sculpture fades away, 

 a sutural furrov/ persisting longest. T.ie first two adult whorls 

 have only radial ribbing. Length of imperfect specimen 1 mm. ; 

 lireadth 2 mm. 



