132 Proceedings of the Royal Society of Victoria. 



Umbilicus covered with a pad that almost fills the umbilical 

 area, the pad sinuously extends to the posterior junction of the 

 columella and outer lip, and is not divided. Aperture lunar- 

 ovate. 



Type, white, with a few slight irregular light brown maculations 

 on the body whorl near the outer lip, another specimen has three 

 encircling rows of dots on the body whorl, and the shell has a 

 light violet tint. 



Dif/ietisiotis of Type. — Height, 4 mm. ; bi'eadth, 4 mm. 



Zf^^rt///}'.— Schnapper Point and Portsea, Port Phillip; Shoreham 

 and San Renio, Western Port. 



Observations. — Type in Mr. Gatliff's collection. 



Natica subcostata, T. Wds.^ (PI. XX., Figs. 1, 2, 3.) 



Shell small, rather thin, globosely turbinate ; whorls, 4 ; 

 smooth, excepting at the upper portion of the whorls immediately 

 below the well defined suture, radiating from which is a con- 

 tinuous series of strongly defined grooves following at somewhat 

 irregular distances, the width between each groove being about 

 three times the width of the groove in the penultimate and 

 ante-penultimate whorls, these grooves extend almost across the 

 whorls, the area near the suture traversed by them on the 

 body whorl is rather depressed. Spire short. Outer lip semi- 

 circular ; inner lip somewhat straight. Deeply umbilicated. 

 Columella somewhat thin, with a very small, narrow, slightly 

 concave callosity entering the centre of the umbilical area. 

 White, covered with a thin, pale straw coloured epidermis. 



Operculum, calcareous, .semilunate, very slightly smaller than 

 the aperture, nucleus small, eccentric anteriorly ; outer surface 

 of the operculum slightly concave, somewhat irregularly spirally 

 grooved, one prominent groove in juxtaposition to the outer 

 margin, but two more strongly defined at a short distance from 

 the margin ; a slight radial marking is also present, showing most 

 distinctly as a slight crenulation at the outer margin. 



Dimetisions of Operculum. — Antero-posterior diameter, 3 mm. ; 

 breadth, 2 mm. ; pertaining to a shell of length, 4 mm., by about 

 the same breadth. 



1 Proc. Linn. Soc. N. S. Wales, 1878, p. 263. 



