BIVALVIA. 131 



Hinnites abjectus, Phil. Tab. XIV, fig. 3, vide antea, p. 125. 



Mitilus (modiola) cuneatus, Sow. Tab. XIV, fig. 9. 



Modtola cuneata, Sow. Min. Con., t. 248, f. 2. 

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



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

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

 subdepresso, superjicie ; 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. 



Mytiltjs (modiola) Leckenbii. Tab. XIV, fig. 8. 



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

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

 superjicie 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. 



