30 Proceedings of the Royal Society of Victoria. 



finely crenulated. The embryonic shell is well marked, 

 apparently smooth and shining, though very small ; the 

 remainder of the shell is finely radially ridged, the ridges being 

 very close, and, as a rule, broader than the intervening spaces, 

 as the shell increases in size fresh ridges make their appearance 

 in the interspaces, at first only thin, but soon reaching the 

 dimensions of the othei^s, so that marginally the ridges are much 

 more numerous ; the radial ridges are crossed by concentric 

 growth lamellae, giving rise to a more or less regular cancellation. 



Dimensions. — Type, greatest length, 5 mm.; greatest breadth, 

 a little over 3 mm.; greatest convexity, about 2 mm. Other 

 examples give about the same dimensions, save that in some the 

 breadth is a good 3-5 mm.; smaller examples range, length, 

 3 mm.; breadth, 2 m.m. 



Locality. — Eocene clays from the Old Cement Works, Bal- 

 combe's Bay, Mornington. 



Observations. — Appai'ently this species is somewhat related to 

 Modiolaria corioensis, Tate, but may be distinguished by being 

 more tumid, and differently sculptured. 



Vepticopdia excavata, sp. nov. 



Description. — Shell small, thin, oblong-ovate, with a prominent 

 produced anterior, umbo prominent and incurved anteriorly a 

 little short of the hinge. Shell only slightly convex, somewhat 

 depressed towards the ventral margin, also to the anterior and 

 posterior ; deeply excavated immediately in front of the umbo, 

 giving rise to a distinct lunule. Inner margin of valve delicately 

 crenulated, and interior of shell nacreous, with a relatively large 

 anterior adductor muscular impression. Externally the surface 

 is sculptured by narrovv acutely angular radial ridges, the 

 interspaces being about twice as broad as the lidges, and very 

 finely transversely striate, ridges number about twenty-eight, 

 and their crests are extremely finely and closely lamellose 

 transversely, the latter feature being most noticeable on the 

 anterior slope, the lamellae apparently being erect. 



Dimensions. — Antero-posterior diameter, 6 mm.; umbo-ventral 

 diameter, 5 mm. (incomplete). 



Locality. — Eocene clays from near the old Cement Works, 

 Balcombe's Bay, Mornington. 



