324 Proceedings of the Royal Society of Victoria. 



tions of length to breadth as C. bulbodes, Tate, ha.s an entirely 

 different habit, the whorls being flattish and running right up 

 to the suture, instead of being tumidly convex subniedially and 

 concave towards the suture, the suture is more canaliculate, the 

 canal is longer and of a more tapering habit, the sculpture is 

 much finer and becomes obsolete sooner. The general habit of 

 this species is very much more of the type of C. longaevus than 

 any other described Australian sjjecies. 



Columbella balcombensis, sp. nov. (PI. XVIIL, 

 Figs. 10, 11). 



Description. — Shell small, tumidly fusiform, with a blunt apex 

 of about three smooth shining and somewhat tumid embryonic 

 whorls, the extreme tip inclined to be elevated. Embryonic 

 whorls succeeded by three to five slightly convex spire-whorls, 

 suture impressed, and the body-Avhorl rather attenuate towards 

 the snout. The smooth embryo is in strong contrast to the 

 highly sculptured whork, and ends off abruptly against the 

 spire ornament. The sculpture of the spire-whorls consists of 

 fine close costulae and rather finer spiral threads which show 

 most strongly in the interspaces between the costulae giving 

 rise to a minute clathrate appearance, the spiral threads in- 

 crease in strength towards the anterior of the shell, being most 

 prominent on the anterior slope of the body-whorl and on the 

 snout. The costulae on the penultimate whorl number about 

 thirty-five to forty. Aperture ovate ; canal very short and 

 slightly bent to the right ; outer lip varicosely thickened and 

 lirate externally, bevelled off internally to a thin edge, fairly 

 strongly denticulate within, the strongest and largest denticle 

 being at the anterior end of the aperture ; inner lip smooth 

 and enamelled, columella somewhat twisted. 



Dimensions. — Leng-th of a four-whorled specimen, 9 mm. ; 

 breadth, 4 mm. ; length rif aperture and canal, 4.5 mm. ; 

 other specimens range 7.5 mm. by 3 mm. : 7 by 3 and 5.5 by 

 2.5; while a five-whorled specimen extends to length, 11.5 

 mm. ; breadth, 5 m.m. 



Locality. — Clays of the old Cement Works, Balcombe's Bay 

 (Type), Grice's Creek and Coast section's, Mornington ; sandy 



