BIVALVIA. 83 



Astarte pumila, Sow. Tab. IX, fig. 13a, b. 



Astarte pumila, Sow. Min. Con., t. 444, f. 2, p. 64. 



— — ? Goldfuss. Petref., t. 134, f. 16. 



— — Morris. Catal. Brit. Foss., 1854, p. 187. 



Testa parvd, convexd, ovatd, umbonibus acutis, postmedianis, antrorsum incurvis, lunula 

 parvd, mediocre depressd, costulis regularibus, oblusis, crebris, interstiis angustioribus. 



Shell small, convex, ovate ; umbones acute, postmesial, but directed somewhat forwards ; 

 hmule small, moderately depressed ; concentric costae regular, obtuse, closely arranged, the 

 interstitial spaces very narrow. 



The height is always greater than the lateral diameter, a character which differs from 

 the shell figured by Goldfuss, the latter probably being a different species ; the depression 

 of the lunule varies in different individuals, but never has the deep concavity figured by 

 Goldfuss. The height is usually about 3 lines ; it is somewhat rare. 



Localities. Ancliff and Minchinhampton. 



Astarte exoentrica . Tab. IX, fig. 8a, b. 



Testa parvd, ovato-orbiculari convexd, umbonibus medianis acutis, Imiuld minima ; plicis 

 incrementi paucis, magnis et irregularibus ; costis crebris depressis, interstiis angustioribus ; 

 costis superioribus subundatis, ewcentricis, inferioribus semel subundulatis sed concentricis. 



Shell small, ovately orbicular and convex ; umbones mesial and pointed ; lunule very 

 small ; folds of growth few, strongly marked, and irregular ; costae very densely arranged, 

 depressed, the interstitial spaces very narrow ; the superior costae are slightly undulated, 

 and are excentric, passing across the surface of the valves very slightly inflected ; the inferior 

 costae are concentric, but are likewise slightly undulated. 



The finely ornamented surface of this little shell is scarcely visible except under a 

 magnifier ; the costae are flattened, and so closely arranged that the interstitial spaces are 

 mere striae ; there is also about the. borders of the costae a kind of obscurely wrinkled 

 appearance, or as though they were slightly crenulated ; the superior or excentric costas 

 occupy a surface less than the inferior ones, and the two kinds are separated by a 

 prominent fold of- growth. Our little species does not appear to be very abundant, it 

 occurs with other small shells of the same genus in the beds of soft shelly Oolite which 

 underlie the planking. 



Height and lateral diameter equal, or about 4 lines. 



Localities. Minchinhampton and Bisley Commons. 



