140 



concentric lines. Inner margin o£ valves not crenulated. Hinge 

 area broad, longitudinally fine-lined ; central tooth v-shaped, 

 succeeded on eacli side by about seven equal lamelliform 

 oblique teeth, delicately crenulated on the sides. 



This species cannot be mistaken for Area pseudojiavicularis, 

 whilst the character presented by the hinge teeth separates it 

 from all congeners. 



Dimensions. — Length, 8 "5 ; width, 4 ; thickness through both 

 valves, 6 millimetres. 



Localities. — Abundant in the lower beds Blanche Point, 

 Aldinga ; and xidelaide bore. 



Barbatia dissimilis, spec. nov. PI. xi., figs. 4 and 5. 



Shell transversely - oblong, somewhat tumid, obliquely 

 rounded in front, subobliquely truncated behind, with a 

 roundly augulated posterior slope. Umbones at about the 

 anterior-third, acute, moderately wide apart ; ventral and dorsal 

 margins nearly parallel, front margin not sinuated. Left 

 valve ornamented with radial ribs crossed by concentric 

 threads, producing imbricating granulations at the intersec- 

 tions. Eight valve with equidistant concentric folds, with 

 pitted sculpture between them. The peculiar sculpture may 

 be the scars of deciduous imbricating scales, traces of which 

 are preserved on the posterior and anterior slopes, particularly 

 on the former, where they are grouped in radial lines. Hinge 

 xirea narrow, with a few marginal longitudinal ridges, and a 

 transverse lanceolate groove beneath the beak and indenting 

 the hinge line. Teeth few, large, transverse, but becoming 

 slightly oblique towards the ends ; about eight in front, and 

 about fourteen behind the umbo. 



Localities. — Very common in the Turritella limestone bands, 

 Blanche Point, Aldinga Bay ; and in the argillaceous glauco- 

 nitic sands, Adelaide bore. 



Limensions. — Length, 7 ; width, .5 ; thickness through both 

 valves, 4 millimetres. 



Barbatia crustata, spec. nov. PI. ii., fig. 16. 



Shell small, oblong, tumid, medially impressed, and sinuated 

 ventrally. L'mbones broad, incurved, approximate, anterior. 

 Anterior side short, roundly truncate ; posterior side elon- 

 gated, obtusely truncated ; posterior slope very narrow, pre- 

 cipitous. Surface with thick concentric lamella, radially 

 plicate or granular. Inner margin of valves plain ; hinge teeth 

 aiumerous, small, transverse. 



Dimensions. — Length, 7 ; width, 3'5 ; greatest thickness 

 through both valves on the posterior ridge, 6 millimetres. 



