188 



Leda vagans, spec nov. 

 Synonym. — L. lucida, Tenison-Woods ; see Part I. (non 

 Loven, id. Jeffreys, Brit. Conch.). 



FAMILY ASTARTID^. 

 Genus Carditella. 



Ilicromeris ruyosa, 31. radiata, and Gouldia lamellata, des- 

 cribed in Part I., prove to be congeneric, and may find a place 

 in Mr. E. A. Smith's genus Carditella, rather than in Micro- 

 meris of Conrad. 



The dentition is as follows : — 



The right valve has one triangular subcentral tooth ; a longi- 

 tudinal posterior tooth separated from the margin by a deep 

 furrow. The left valve has two divergent cardinal teeth, and 

 a longitudinal anterior tooth separated from the margin by a 

 shallow furrow. 



The acute posterior edge of the left valve is received in the 

 furrow of the right valve, and the acute anterior edge of the 

 right valve fits into the furrow of the left valve ; in conse- 

 quence of this the right valve overlaps the left valve on the 

 posterior hinge line, and the left overlaps the right on the an- 

 terior hinge line. 



In C. radiata the lateral teeth and furrows are transversely 

 striated, and there is sometimes developed a small supplemen- 

 tary laminate cardinal tooth in either valve. 



Two new species are here added. 



SYNOPSIS OF TIIE SPECIES. 



Shell trigonal. 



Ornament of fimbriated imbricating lamella?. C. rugosa. 

 Ornament of radial ridges and simple folds. C. radiata. 

 Surface smooth, slightly inequilateral. C. polita. 



Shell subquadrangular. 



Ornament of 20 thin lamella?. C. lamellata. 



Densely lamellated. C. multilamella. 



Carditella polita, spec. nov. Plate xx., figs 20 and 21. 



Shell trigonal, compressed with produced rather straight 



umbones ; the young shells are equilateral, but in the adult 



the anterior side is slightly produced. The surface is polished, 



indistinctly marked with concentric lines. The inner margin 



of the valves is finely crenulated all round. The cardinal tooth 



in the right valve is stout and sulcated on the crown as in 



C. radiata. 



Dimensions. — Antero-posterior and umbo-ventral diameters, 

 25 millimetres. 



Locality. — Lower and upper beds at Muddy Creek ; gas- 

 tropod bed, Kiver Murray Cliffs near Morgan. 



