732 STUDIES ON AUSTRALIAN MOLLUSCA. 



umbo. The medio-posterior panel extends from a line vertically 

 below the beak to a line from the beak to the centre of the 

 posterior margin, and is occupied by a dozen rather strong, widely 

 spaced, straight, radiating ridges. The posterior panel contains 

 low, broad and strong folds, meeting the radiating ridges at an 

 acute angle. 



The radial sculpture slightly crenulates the ventral margin and 

 furrows the interior. Pallial sinus rounded, deep, extending to 

 the centre of the valve. Lateral hinge teeth absent Cardinals : 

 in the right, one, in the left, two; the right and posterior left 

 notched and furrowed; the anterior left large and fitting into a 

 deep socket in the opposite valve. Length, 16 ; height, 11 ; 

 breadth of conjoined valves, 7-5 mm. 



EXPLANATION OF PLATE XLVIII. 



Figs, 1-3. — Endodonta concinna, Hedley; in various aspects. 



Figs. 4-8. — Asaphis contraria, Deshayes; in different aspects, with details of 



hinge and muscle scars. 

 Fig. 9. — Blauneria leonardi, Crosse. 

 Fig. 10. — Stenothyra australis, Hedley. 

 Fig. 11. — Petterdiana thaanumi, Pilsbry. 

 Fig. 12. — Iravadia australis, Hedley. 



Figs. 13-14.— Mathilda rosa, Hedley; in different aspects. 

 Fig. 15. — Leuconopsis inermis, Hedley. 

 Fig. 16. — Leuconopsis obsoleta, Hutton. 



Figs. 17 -19.— Chlamys fenestrata , Hedley; exterior, hinge and sculpture. 

 All enlarged and to various proportions. 



