82 MOLLUSCA FROM THE GREAT OOLITE. 



Astarte. Sow., 1817. 



Gen. Char. Shell equivalve, inequilateral, thick, the surface usually concentrically costated, 

 the margins of the valves close, and internally crenulated. Hinge with two diverging cardinal 

 teeth in each valve, those of the left valve being elongated and nearly equal, those of the 

 right valve unequal, the anterior one being small. Muscular impressions two ; ligament 

 external. 



Astarte squamula, D'Archiac. Tab. IX, fig. 9. 



Astarte squamdla, D'Archiac. Mem. Soc. Geol. Fr., vol. v, pi. 25, f. 5. 



Testa ovato-orbiculari, subdcprcssd, umbonibus mediants acutis, lunula ovato-lanceolatd, 

 costis concentricis, erebris, irregularibus et depressis, nonnunquam obsoletis. 



Shell ovately orbicular, rather flattened ; umbones mesial, prominent, and acute ; lunule 

 ovately lanceolar, and but little excavated; hinge margin lengthened and rounded; concentric 

 costa3 numerous, irregular, and depressed, sometimes obsolete. 



The valves of this little depressed species occur in considerable numbers throughout the 

 shelly beds of the formation in the Minchinhampton district ; in the greater number of 

 instances the surface is smooth, probably by erosion. The lateral diameter is one fifth 

 greater than the height, and in the largest examples does not exceed six lines. 

 Individuals vary moderately, both in the outline and the convexity of the valves, but a 

 considerable number can easily be obtained for comparison. 



Localities. Minchinhampton. Eparcy, France. 



Astarte minima, Phil. Tab. IX, fig. 10a, b. 



Astarte minima, Phil., Geol. Yorksh., t. 9, f. 23. 

 ? Astarte pulla, Roemer, Nordd. Ool., p. 113, t. 6, f. 26. 



Testa convexd, ovato-orbiculari ; umbonibus submedianis ; costis regidaribus convexis, 

 interstiis arpialibus {circa 14). 



Shell convex, ovately orbicular; umbones nearly mesial; costas (about fourteen in number) 

 regular, rounded, elevated, and equal in breadth to the interstitial spaces. 



This little shell is not associated with any other at all resembling it, but from its 

 minuteness, it is probably often unnoticed ; it does not appear to be abundant (at least in 

 the Minchinhampton district, from which our specimens have been obtained). 



The lateral diameter exceeds the height by about one third, and rarely equals 4 

 lines. 



Localities. Minchinhampton Common, in the soft beds of Oolite beneath the planking ; 

 Ponton, Lincolnshire ; Scarborough, in the grey limestone of the Great Oolite. 



