133 



Leda 'Woodsii, spec. nov. PI. is., fig. S. 



Synonym. — L. inconspicua, Teui sou-Woo els, in Vvoc. Linn. 

 Soc, N.iS.W., vol. iii., p. 139, t. 21, fig. 3, 1878 {iion A. Adams). 



Shell small, compressed, oblong subovate ; umbos post- 

 median, small, depressed ; posterior side rather longer than 

 -the anterior side, obtusely triincated and acuminated at the 

 «ud ; anterior side rounded, somewhat attenuated ; dorsal 

 margin sloping anteriorly, nearly straight posteriorly. An 

 angular posterior ridge originating at the umbo circumscribes 

 a triangular depressed area. Surface finely concentrically 

 ribbed, less conspicuously so on the anterior side ; the ribs 

 pass over the umbonal ridge on to the depressed area above. 

 Lunule ill-defined, narrow elongate ; ligamental pit triangular, 

 deeply sunk. 



Dimensions. — Length, 12 ; height, 6 ; thickness through both 

 valves, 3 '5 millimetres. 



Localities. — Muddy Creek, Hamilton {Ten. Woods!)-, gas- 

 tropod bed. Middle Murravian, near Morgan (B.T.). 



The Eev. J. E. Tenison-Woods figures a young shell o£ this 

 >species under Adams' name of i. inconspicua. Certainly it 

 closely resembles Eeeve's figure of that species, but at later 

 stages of growth the resemblance ceases, and the general form 

 is that of L. Borhnii, Hanley. Without specimens it would 

 not be possible, I think, to differentiate the fossil from the 

 living species above named ; but the result of an actual com- 

 parison of specimens is that the fossil differs in the following 

 particulars : — Hinge line more arched, anterior side more 

 attenuated, the concentric ridges more numerous and finer. 



Young examples of L. Woodsii differ from L. crehrecostata, 

 Woods, in being more oblong and with finer concentric ridges, 

 both agreeing in the short triangulated rostral prolongation. 



Leda crebrecostata, Tenisou-Woods. PL v., figs. 5a— oh. 



Reference. — Proc. Eoyal Soc, Tasmania, vol. for 1877, p. 



Shell small, moderately depressed, transverse trigonal, nar- 

 rowly oblong ; umbo post-median ; anterior side the longer 

 roundly obtuse, posterior side shortly rostrated, triangular, 

 rather compressed and obtusely truncated at the end. Surface 

 regularly concentrically ridged with equal rounded ribs. 



"Hinge line inconspicuous and short, anterior subligamental 

 .area distinct. 



" Transverse length, 5 ; breadth, 8 ; thickness of both valves 

 joined, 3 millimetres" (T. Woods). 



Locality. — Table Cape {R. M. Johnston !). 



It is smaller and less oblong than L. DoJirnii, Hanley, but 

 like it distinguished by the abrupt angulation of the posterior 

 margin and the concentric thick rounded ridges. 



