MOLl.USCA — HKDMCV. 



:i09 



the foreign Ixnly to uhirli llit^ ii\)v\ is lixe( 

 tions early appear, increase by interstitial 

 riblets, and corrugate the margin. 

 Interior with a marginal shelf reached by 

 variable radiating ribs, which are not 

 related to the external sculpture, the 

 ventral distant, the dorsal smaller and 

 closer, sometimes in pairs. Hinge line 

 straight and short, beneath its centre is 

 set the small deep triangulai- chondro- 

 phore. Umbo projecting in the left 

 valve. Height, 12 ; length, 10 mm. 



My material consists of fragments 

 and odd, mostly left, valves. .A 11 known 

 Dwiya are Tertiar}'' fossils except D. 

 argentea, Dall,* dredged alive in the 

 West Indies. From that the Australian 

 shell differs by coarser sculpture and 

 fewer internal radii. Two Australian 

 Eocene Dimya were published by the 

 late Prof. Tate. D. dissimi/is,j which 

 has wrinkled hinge areas like Dimyadon, 

 and D. sigillatal, apparently from the 

 examples before me, smoother, smaller, 

 and more globose than the recent species. 



The interior of the left and the 

 exterior of the right valve are here figured 



Off Port Kembla, 63-75 fathoms. 



radial crenula- 



DlMTA CORRUGATA. 



Fig. 52. 



LIMA, Bruguiere. 

 LIMA LIMA, Linn., var. MULTICOSTATA, Sotvevhy. 



Lima mtdticostata, Sowerby, Thes. Conch., i., 1843, p. 85, pi. xxii.^ 

 f. 38. 



Stations 48, 49. 



Several living specimens from 63-75 fathoms off Port Kembla 



and off Wollongong in 55-56 fathoms. 



» Dall— Bull. Mus. Comp. Zool., xii., 18S5-6, p. 228. 



t Tate -Trans. Eoy. Soc. S.A., vii., 1885, p. 100, pi. iii., f. 9a-c. 



X Tate— Op. cit., pi. viii., i.\Sa-h. 



