THE CORALLIAN ROCKS OF ENGLAND. 397 



AsiARTE AYTONEN8IS, LyCett. PL XIV. fig. 11. 



A very remarkable form in the Leckenby collection has long gone 

 under the name given it by Bean ; and a similar shell is described 

 by Dr. Lycett from the Great Oolite. It is elongated and sub- 

 quadrilateral ; height | the length ; valves very depressed ; umbones 

 ^ the length from the anterior end, not very prominent, subin- 

 curved ; ventral margin undulating, drawn in opposite the umbo ; 

 posterior margin obliquely truncated ; anterior margin gibbous ; 

 dorsal posterior margin straight, horizontal ; anterior sigmoidal : 

 ornaments, regular large ribs following the contour of the ventral 

 margin. 



Length 1| inch. 



The specimen figured is from a suboolitic matrix at Ayton ; and 

 the species also occurs in the Coral Rag of Upware. 



Ctprina tancrediforjus, spec. nov. PI. XV. figs. 1, la. 



Shell subtrigonal ; height from umbo -| the length ; valves only 

 moderately convex. Umbones prominent ; posterior side flattened, 

 and the end truncated ; anterior ventral margin curving rapidly up 

 to meet the anterior dorsal margin, producing the appearance of a 

 beak, as in a Tancredia ; dorsal margin running to an angle beneath 

 the umbo ; surface smooth, shining. Hinge fairly comparable to 

 that of a Cyprina. 



This has a very great resemblance to a Tancredia, but it has 

 scarcely the hinge of that genus. 



In the Lower Calcareous Grit (Nothe grits), Weymouth, and 

 abundant as casts at Highworth. 



Cypricardia glaera, spec. nov. PI. XV. figs. 2, 2 a. 



Shell roundly triangular ; height equal the length ; valves in- 

 flated ; umbones rather prominent, nearly median ; surface smooth. 



Length § inch. 



There is little to characterize this shell. It is more inflated than 

 most of its congeners, and the posterior ridge is very feebly marked. 



In the Trigonia-heds of Weymouth, and many other parts of the 

 series both in the south and north of England. It is somewhat re- 

 markable that so plentiful a shell should have escaped the notice of 

 authors, though it is just possible that some of the figures by De 

 Loriol may be intended for this species. 



Protocardium isocardioides, spec. nov. PI. XIV. fig. 12. 



Shell inflated, umbones very prominent, incurved ; radiating lines 

 very fine and scarcely observable, confined, as usual, to the posterior 

 side. 



This is so strongly inflated that it has very much the aspect of an Iso- 

 cardia, under which genus it has certainly been known in collections. 



In the Trigonia-heds, Osmington and elsewhere. 



The Yorkshire forms which we have cited by this name may very 

 possibly represent the Gardium lobatum of Phillips, which is badly 

 characterized, and undeterminable from the figure alone. 



