BIVALVIA. 59 



LuciNA ? BuHTONENSis, Lyc. Tab. XL, figs. 20, 20 a, 20 h. 



Testa suborbiculata, dcpressa, umhonihus suhangulatis antrorsum curvatis, latere postico 

 area dcpressiuscula, si/perficie striis teniiihus concenfricis crebris notatis. 



Shell suborbicular, depressed ; unibones antero-mesial, angnlated at their extremities, and 

 curved forwards ; the posterior side has a depressed, obhque area, without any angle ; the 

 surface has very delicate, closely arranged, regular, concentric striations ; the hinge-border 

 is short, and slightly curved. 



As the hinge has not been exposed, some doubt may exist whether it is really a 

 Lucina ; the umbones are more produced than is commonly seen in that genus. 



Geological Position and Localiti/. The Forest ]\Iarble of Burton Bradstock, Dorset, in 

 the collection of W, Walton, Esq. 



Lucina Beanii, Bean, sp. Tab. XXXVIII, fig. 3. 



AsTAUTE RoTUNDATA, Bean. Mag. Nat. Hist. 1839, non Roemer. 



Testa tumida ovato-obliqua, umbonibus antemedianis, mac/nis, incurvis, marline cardinali 

 obliqiie-declivi, curvato, margine antico brevi, arcuato curvato ; valvis striis irregularibus, 

 plicisque semel instructis. 



Shell somewhat inflated, oblique, ovate ; umbones prominent, obtuse, incurved, placed 

 anterior to the middle of the valves ; hinge-margin lengthened, curved, sloping obliquely 

 downwards ; anterior margin short, rounded ; lunule very slightly excavated ; the surface of 

 the valves has irregular, concentric striations, and also a few large plications of growth. 

 The interior has not been exposed, but neither the hinge-margin nor the anterior border 

 possesses the usual characters of Astarte, the lunule being nearly obsolete. It is shorter 

 and more convex than Lucina crassa, nor does it nearly resemble any other contempo- 

 raneous species. 



Height and lateral diameter nearly equal ; diameter through both the valves, one 

 third less. 



Geological Position and Localiti/. The Cornbrash of Scarborough, in the collection of 

 Mr. Leckenby. 



CoRBis Neptuni, Lt/c. Tab. XXXV, fig. 19. 



Testa transverse ovali subaquilatera, concentrice costata, margine cardinali curvato, 

 oblique declivi, lunula magna excavata, umbonibus medianis subdepressis, antrorsum curvatis ; 

 costis concentricis regularibus angustis, striisque intersiitiis instructis. 



Transversely oval, convex, nearly equilateral ; umbones rather depressed, curved for- 



