132 



teriorly ; anterior side rounded ; ventral margin rather straight 

 in the middle, abruptly sloping upwards posteriorly ; posterior 

 side somewhat angular, shortly acuminate above. Surface 

 marked with concentric folds and striae of growth. Lunule 

 Avell-defiued, elliptical, striated; cardinal teeth, 20 in front row, 

 15 in the posterior row. 



Dimensions. — Length, 18; height, 11; thickness through both 

 valves, 8 millimetres. 



Localities. — Corio Bay ; common at Muddy Creek ; Schnapper 

 Point ; and near Morgan {B. T.) 



L. lucida was established upon a minute shell, which I have 

 been enabled to trace through various stages of growth to the 

 moderately large- si zed example figured on pi. vi., fig. 7. The 

 original diagnosis reads as follows: — "Shell small, tumid, solid^ 

 polished, equilateral, almost ovate, regularly concentrically 

 ribbed ; ribs rounded equal ; j)osterior side scarcely produced, 

 subacutely angular, posterior angle scarcely sulcate ; anterior 

 side short, obtusely rounded, umbone subacute. Long. S'S, 

 lat. 5'5, alt. 2 millimetres. Muddy Creek." 



Professor McCoy, in Eep. Greol. Surv. Victoria, 1875, p. 22, 

 figures the cast of a shell obtained at Stawell, which he says 

 "is the Nucula Marthce (McCoy), an extinct species common 

 in the Oligocene Tertiary beds between Mount Eliza and Mount 

 Martha." I have no doubt that the JSF. Martliod above referred 

 to is conspecific with i. lucida^ though of the many examples in 

 all stages of growth from that particular locality which I have 

 examined, I cannot find one to match the drawing in the Geol. 

 Surv. Report. The drawing may imperfectly represent the 

 shell ; however, as it does not serve for identification, and as 

 no diagnosis has been published of the species, I prefer to em- 

 ploy the name given by Tenison Woods. 



Leda praelonga, spec, nov. PI. xii., figs. 4a — 4&, 



Shell small, transversely ovate, very inequilateral, rather 

 compressed, smooth, shining ; umbones post-median, incon- 

 spicuous ; anterior side ventricose, rounded, produced ; pos- 

 terior side short, rather attenuated and bluntly acuminate ; 

 valves closed ; pallial sinus conspicuous. 



Dimensions. — Length, 4; height, 2 ; thickness through both 

 valves, 1 millimetres. 



Localiiies. — Table Cape, Tasmania ; and Muddy Creek, 

 Hamilton, Victoria. 



This is a very distinct species, and cannot be mistaken for 

 young examples of associated species ; it makes some approach 

 ito L. leptorhynclia, but differs from it by its shape and the 

 position of its inconspicuous umbones. 



