margin is nearly horizontal, thence rapidly ascending to the 

 somewhat apiculate front extremity. 



Sculpture. — On the umbonal region it consists of concentric 

 ridges and raised radial lines ; the interspaces between the 

 ridges are concentrically striated and decussated by the radial 

 lines. Proceeding outwards the ridges are gradually developed 

 into thin, erect, crowded, crenately-wrinkled laminae, which 

 towards the posterior margin are broader and frilled ; the 

 radial lines of the umbonal area are continued as opaque pinkish- 

 white thickenings in the crenatures on the dorsal face of the 

 otherwise pellucid lamellae. 



Colour greyish, with a purplish or flesh-coloured stain about 

 the umbones and posterior area. 



The pallial line which is stained brown is near the margin ; 

 the sinus is narrow rather short and acute at the apex ; the post 

 adductor scar is purplish-brown and the anterior one pale-horn. 



Dimensions. — Antero-posterior diameter, 21 ; umbo-ventral 

 diameter, 14 ; sectional diameter, 13 millimetres. 



Locality. — Burrowing in stiff clay on the north side of the 

 mouth of the Eiver Patawalonga, Holdfast Bay. 



This species differs from all known species having lamellose 

 ornament by its attenuated front and crowded lamellae. 

 Corbicula desolata, spec. nov. Plate iv., figs, 11a— b. 



Shell subtrigonally ovate, subequilateral, very convex with 

 very prominent umbones ; anterior side shorter, rounded at the 

 margin, posterior margin more sharply curved. 



Epidermis glossy, straw-coloured in young examples, brown 

 in the adult. The ornament consists of distant, regular, acute, 

 concentric ridges, passing into crowded raised lines on the pos- 

 terior side where the epidermis is dull, darker in colour, and is 

 crossed by fine oblique filaments. 



Ligament short, brown. Interior of the valves bluish-white 

 towards the margins, opaque-white towards the umbones. 

 Hinge with three cardiual teeth in the right valve ; the anterior 

 one is small, the other two are grooved on their summits ; the 

 sockets for the lateral teeth are transversely striated. The 

 left valve has two cardinal teeth, and the lateral teeth are 

 transversely striated on both faces. 



Dimensions. — Antero-posterior diameter, 17 ; uuibo-ventral 

 diameter, 15 ; sectional diameter, 11 millimetres. 



Locality. — Cooper's Creek at Innamincka, Central Australia 

 (Mr. James McLeod 7) . 



O. desolata is related to C. Anyasi, but differs by its more 

 equilateral outline and great convexity, 



Lucina crassilirata, spec. nov. Plate iv., fig. 2. 



Shell orbicular, subglobose, very thick, regularly convex except 

 in the post-dorsal area which is abruptly compressed. Surface 



