136 CRETACKUUS LAMbJLLiUUAM'll 1 A. 



Ijut is much lari^vr ami stouter, and the luimlar reg-ion is more deeply excavated; 

 also the uinliniies appear to have a greater anterior curvature. 



Type. — From Benniworth Haven, in the Sedgwick Museum. 



Bidrlhntiun. — Claxby Ironstone (zone of Bclemnitcs lateralh) of Benniworth 

 Haven and Donnington. 



CyI'EIXA teali;ikxsi8, sp. no v. Plate XX, fig. Von, h. 



Dcscriptiuii. — Shell very thick, large, elongate, oval, regularly convex, very 

 ine(|uilateral. Antero-dorsal margin concave. Anterior margin rounded, curving 

 rapidly, passing gradually into the ventral margin. Posterior margin rounded, 

 forming an obtuse angle with the long, slightly convex postero-dorsal margin. 

 Umbones broad, anterior, curved inward. A faint carina extends from the umbo 

 to the po.sterior end. Luuular region deep. Escutcheon large, deep, limited by a 

 strong carina. Ornamentation consists of growth-ridges. 



Measurement^! : 



(1) (-') 



Length .... 105 .. 62 mm. 



Height . . . . 82 . . 49 „ 



(1, i) Tealby Limestoue. 



Affinifirs. — In its elongate form, and deep, carinate escutcheon this species 

 resembles G. huluniensi.s, de Loriol,i from the Portlandian. 



Iiemarls. — There are two specimens in the Sedgwick Museum and one in the 

 British Museum. The hinge has not been seen. 



Dldv'ibutiun. — Tealby Limestone of Walesby and Claxby, Lincolnshire. 



CvriiiXA, sp. Plate XXT, fig. 3. 



A large Gi/priiKi from the Tealby Limestone of Claxl)y is known by a right 

 and a left valve, now in the Sedgwick Museum, and appears to belong to a distinct 

 species. It shows some resemblance to G. niKjnbttn, Sowerby (sec page 141), Ijut 

 differs from that species in the greater ventral slope of the postero-dorsal mai-gin ; 

 the greater obliquity of the jiostcrior margin ; tie smaller ciirvature of the 

 umbones ; the longer and less concave antero-dorsal margin ; and in the absence 

 of a carina cutting off a postero-dorsal area. The surface of the shell is 

 imperfectly preserved, but in places there is evidence of well-marked gi-owth- 

 ridgcs. Length, 92 nnn. Height, 80 mm. 



' De Loiiol aud iVllat, ' Porlliiudicu du Boulogue-sur-Myr ' (18(JG), p. h-k pi. v, fig. 9. 



