155 



sub striated in the interstices, and radiately striated, more con- 

 spicuously so on the posterior and anterior sides ; the lamellae- 

 are about 40 in number, thin, elevated, and radially ribbed 

 and striated on the ventral aspect. 



Margin of the valves from the umbo to the post-ventral 

 angle minutely crenulated. Siphonal inflection very short, 

 broadly triangular. 



Dimensions of a moderate-sized specimen. — xlntero-posterior 

 diameter, 38 ; umbo-ventral diameter, 30 ; sectional diameter 

 through both valves, 22 millimetres. 



Localities. — Abundant in the Turritella clays at Blanche 

 Point, Aldinga Bay, and in the clayey green sands in the Ade- 

 laide bore. 



C. multilamellata bears considerable resemblance to Venus 

 oblong a, Hanley, but is not so rounded posteriorly and the 

 lamella? are higher and thinner. 



Ghione hormophora, Tate. Plate xv., figs, la — 1&. 



Reference. — Proc. Eoy. Soc, Tasmania, for 1884, p. 230. 



Shell solid, cordately-ovate, inflated ; truncately rounded in 

 front, truncated behind ; ventral margin arched ; post-dorsal 

 margin strongly arched, antero-dorsal margin straight. Sur- 

 face ornamented with numerous concentric lamella? thickened 

 and recurved, becoming erect and thin towards the posterior 

 and anterior margins ; the interstitial spaces with numerous 

 flattish radial ridges, about equal in breadth to the intervening: 

 sulci, which are continued on to the bases of the concentric 

 folds, and to the the free margin of the frills on their under- 

 sides. Lunule cordate, not much impressed under the umbo, 

 and indistinctly margined. The umbo is in the anterior-fifth, 

 large, incurved, and directed forwards. Inner margin of 

 valves, excepting that of the post-dorsal region, is minutely 

 crenulated. Posterior cardinal tooth in left valve is quadrate 

 and bituberculated on the crown. Pallial sinus short, broadly 

 triangular, apex acute. 



Dimensions. — Antero-posterior diameter, 65 ; umbo-ventral 

 diameter, 57 ; sectional diameter of left valve, 22 millimetres. 



Locality. — Table Cape (R. 31. Johnston .') 



Chione dimorphophylla, Tate. Plate xv., figs. 3a — 3b. 



Reference. — Proc. Eoy. Soc, Tasmania, for 1884, p. 230. 



Similar to C. hormophora, but is more regularly rounded at 

 the front, is less inflated, the umbo placed more posteriorly ; 

 the lunule is more impressed and concave ; and the relative 

 dimensions are different. 



Dimensions. — Antero-posterior diameter, 58 ; umbo-ventral 

 diameter, 45 ; sectional diameter of both valves, 32 milli- 

 metres. 



