BIVALVIA. 131 



HINNITES ABJECTUS, Phil. Tab. XIV, fig. 3, vide antea, p. 125. 

 MITILUS (MODIOLA) CUNEATUS, Sow. Tab. XIV, fig. 9. 



MODIOLA CUNEATA, Sow. Min. Con., t. 248, f. 2. 



Phil. Geol. York., 1, t. 5, f. 28. 



Testa ovato elongatd, convexd ; umbonibus subterminalibus parvis curvalis, acutis ; margine 

 antico subsinuato ; margine cardinali oblique declivi, curvato, dorso obtuse fornicato, antice 

 subdepresso, superficie ; lineis concentricis tenuissimis irregularibus. 



Shell ovately elongated, convex ; umbones nearly terminal, acute, and incurved ; hinge 

 margin sloping obliquely and curved; anterior margin nearly straight, but slightly 

 sinuated ; dorsal surface obtusely ridged, most elevated about the middle of the valve, 

 forming a depressed surface anteriorly and obliquely to it ; the surface with fine irregular 

 concentric lines or striations. 



The acute umbones, depressed and wedge-shaped anterior side, and slight obliquity of 

 the entire form, serve to distinguish it from other species of the Lower Oolites. 



Geological position and localities. At Scarborough, in the Great Oolite ; Somerset- 

 shire, in the Inferior Oolite. 



MYTILUS (MODIOLA) LECKENBII. Tab. XIV, fig. 8. 



Testa ovato, arcuatd, convexd, acutd et oblique fornicatd ; antice angusto postice lato ; 

 umbonibus subterminalibus acutis ; dorso fornicato, latere anteriore sulcato et sinuato ; 

 superficie striis tenuissimis, crebris, irregularibus. 



Shell curved, ovate ; anterior extremity rounded but narrow, posterior extremity wide 

 and curved obliquely ; umbones nearly terminal and acute ; dorsal surface with an elevated 

 narrow ridge, anterior to which is a depressed and sinuated surface, the anterior border of 

 which is much excavated, and its lower extremity rather pointed; the hinge margin is 

 lengthened, sloping downwards obliquely, and but very slightly curved ; the surface has 

 closely arranged very fine concentric striations. 



The great obliquity of the valves, the deeply sinuated anterior border, the pointed 

 inferior extremity, and the flattened but raised posterior surface, will serve to distinguish 

 it from Mytilus (Modiola} bipartita, to which its acute dorsal ridge presents a resemblance. 



Length, 16 lines ; opposite diameter, 8 lines ; diameter through both the valves, 8 lines. 

 The name is in complement to John Leckenby, Esq., of Scarborough, to whom we are 

 indebted for the loan of the specimen. 



Geological position and locality. The Great Oolite of Scarborough, in a bed of hard 

 grey ferrugino-micaceous sandstone. 



