Hutton. — On new Tertiary Shells. 331 



anterior further apart. Anterior dorsal margin very short ; the posterior 

 dorsal margin slightly concave. Anterior end flatly rounded. Ventral 

 margin flatly rounded. Posterior end rounded. 



Length, 2-75 inch ; height, 2-0 inch. 



Locality. Oamaru and Broken Eiver. 



The type is in the Otago University Museum, from Oamaru. It was 

 presented by Mr. J. Ashcroft, but the exact locality is not known. 



Mactra lavata. 



Shell oval, thin, inequilateral, smooth, rather compressed. Dorsal 

 slopes nearly straight, the posterior much longer. Ventral margin rounded. 

 Posterior end tapering, but not truncated nor angled. The whole shell with 

 very fine concentric lines which are seen, under a lens, to be crossed by 

 excessively minute radiating lines, giving a delicate granulated appearance. 

 Eight valve with two strong anterior and two equally strong posterior lateral 

 teeth ; short and high, the inner on both sides being higher than the outer. 

 Left valve with one lateral on each side ; longer than those of the right 

 valve. 



Length, *9 inch ; height, *75 inch ; thickness, *42 inch. 



Locality. Petane. Collected by Mr. A. Hamilton. 

 Loripes laminata. 



Shell small, orbicular, the umbo turned forwards, compressed, finely 

 distantly laminated and radiately striated between the lamella. Dorsal 

 anterior margin hollowed ; the posterior dorsal margin slightly convex ; the 

 ventral margin rounded. Anterior muscular impression elongated. 



Length, -28 inch ; height, *27 inch. 



Locality. White Eock Eiver. 



Differs from L. concinna in the greater distance of the lamellas and in 

 the radiate striation. 



Macrodon (Cucullaria) australis. 



Right valve. Shell transversely sub-oval, inequilateral, moderately in- 

 flated, radiately finely ribbed, the ribs apparently scaly. There are about 

 60 of these ribs near the margin, but many die out towards the umbo. 

 Margin of shell crenated ; the posterior margin perpendicular to the hinge 

 line. Umbos rather anterior, incurved, slightly separated. Hinge area 

 narrow, crossed obliquely by one anterior and one posterior line radiating 

 from the umbo. Hinge line very slightly curved ; two or three small teeth 

 below the umbo, in front of which are four and behind it five teeth, all 

 of which are nearly parallel to the hinge line ; making about 12 teeth in 

 all. 



Length, *5 inch ; height *4 inch. 



Locality. White Eock Eiver and Mount Horrible. 



