86 MOLLUSCA FROM THE GREAT OOLITE. 



lunule elliptical, narrow ; cardinal margin nearly straight, oblique ; concentric costse convex, 

 irregular, with fine interstitial concentric striae. 



The lateral diameter is one fifth greater than the height ; the smaller specimens arc; 

 those which display the characters of the species most distinctly ; with increase of growth 

 the shell acquired some additional convexity, and the costae became less distinctly 

 elevated. 



Locality. It occurs somewhat rarely in the shelly beds of the formation at Minchin- 

 hampton, and likewise in the middle division of the Inferior Oolite of the same district. 



Astarte angulata. Tab. IX, fig. 17 a, b. 



Testa crassd transversa, subtetragond, aid cuneiformi ; umbonibus anticis promi- 

 nentibus ; margine antico rotundato, postico elongato, subrostrato, dorso oblique subinflexo ; 

 ■striis concentricis crebris, irregularibus. 



Shell thick, transverse, somewhat triangular or wedge-shaped ; umbones prominent and 

 anterior ; anterior margin short and rounded ; posterior margin elongated, slightly curved, 

 and rostrated ; dorsal surface slightly bent by an obscure angle, which passes obliquely 

 downwards to the posterior extremity; striae concentric, closely arranged, and irregular. 



A sulcus borders the posterior side of the shell throughout its length ; it is smooth, 

 and the margin separating it from the dorsal surface is acute. This character will readily 

 distinguish it from contemporaneous species of the genus. 



This small shell is not very common : it occurs with other small Veneridae in the soft 

 Oolite which underlies the planking. 



Locality. Minchinhampton Common. 



Astarte elegans, Sow. Tab. XIV, fig. 14. 



Astarte elegans, Sow. Min. Con., t. 137, f. 3. 



— — Phil. Geol. York., 1, t. 11, fig. 41. 



— — Gold/. Petrel'., t. 134, f. 12. 



— — Zeiten. Petref., t. 61. f. 4. 



— — Morris. Catal., 1854, p. 186. 



Testa ovato-obliqud pla?w-convexd, crassd; umbonibus antemedianis prominentibus ; 

 lunula cxcavatd, marginibus rotundis ; laieribus plicis concentricis magnis elevatis subacutis, 

 plerumque regularibus ; marginibus intends denticulatis. 



Shell ovately oblique, with a low convexity; test thick ; umbones prominent, anterior, 

 and curved forwards ; lunule excavated ; border of the valves rounded ; surface with large, 

 elevated, and rather acute, usually regular concentric plications ; inner margins of the 

 valves denticulated. 



Specimens vary much in the degree of obliquity and convexity. 



