76 MOLLUSCA FROM THE GREAT OOLITE. 



CYPRICARDIA NUCULIFORMIS, Roemer, sp. Tab. VII, fig.10, 10a, b.. 



CYBENA NDCULIFORMIS, Roemer. Verst. Oolith., t. 9, f. 13, 1836. 



Testa subtrigond aut cuneiformi, incequilaterd ; umbonibus anticis confirms, marline 

 antico rotunda, postico elongato et recto, basi curvatd, subsinuatd, cardine bidentato dentibus 

 lateribus magnis. 



Shell subtrigonal or cuneiform, very inequilateral ; umbones anterior, contiguous ; 

 anterior margin rounded, posterior margin elongated and straight ; base curved, slightly 

 sinuated ; hinge with two cardinal teeth in each valve and a large lateral tooth placed at 

 some distance from the others. The general form is rather compressed ; the concentric 

 plications are distinct, but not very prominent. 



It occurs somewhat rarely in the shelly beds of the formation, also occasionally in the 

 upper beds in the form of casts. 



Height 8 lines; length, 12 lines; diameter through both the valves, 5 lines. 



Locality. Minchinhampton Common. 



* 



HIPPOPODIUM, Sow. 1819. 



A solitary specimen of this genus has been found by us in the Stonesfield slate of 

 Oxfordshire ; unfortunately it is in too imperfect a condition for description or comparison, 

 but it bears a general resemblance to some specimens of H. ponderosum, Sow., and we 

 have recorded the fact of its occurrence with the view of drawing further attention to the 

 subject. 



MTOCONCHA, Sow., 1824. 



Gen. Char. Shell equivalve, transverse, very inequilateral, umbones small, depressed, 

 subterminal ; hinge border lengthened, straight, having an external elongated groove 

 parallel with it, and extending from the umbo posteriorly to the extremity of the shell, 

 ventral margin entire, not sinuated, and parallel with the hinge border. Hinge, with an 

 elongated cardinal tooth in the right valve, situated beneath the umbo, and which is 

 received into an elevated cavity in the other valve ; there is also in each valve a lengthened 

 posterior thickened plate or rib, serving to support the ligament, which is external. 

 Muscular impressions, two in each valve, of which the anterior are rounded, and bounded 

 internally by an elevated and thickened plate which projects from beneath the cardinal 

 tooth ; posterior impression expanded ; palleal impression not sinuated. 



MYOCONCHA CRASSA, Sow. Tab. Ill, fig. 16, 160. 



MYOCONCHA CRASSA, Sow. Min. Con., t. 467, 1824. 



Bronn. Leth. Geog., p. 237, t. 20, f. 15, 1851. 

 MYTILUS SULCATCS, Gold/use. Petref., t. 129, f. 4, 1840. 



