BIVALVIA. 83 



Astarte pumila, Soiv. 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, umbonibiis acutis, postmedianis, antrorsum incurvis, lunula 

 parvd, mediocre depressd, costulis regidaribus, obtusis, crebris, interstiis angustioribus. 



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

 lunule small, moderately depressed ; concentric costse 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 excentrica. Tab. IX, fig. 8a, b. 



Testa parvd, ovato-orbiculari convexd, umbonibiis mediants acutis, lunula minima ; plici-s 

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

 cosiis superioribus subundatis, excentricis, 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; costse very densely arranged, 

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

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

 costse are concentric, but are likewise slightly undulated. 



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

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

 mere strise ; there is also about the borders of the costse a kind of obscurely wrinkled 

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

 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. 



