S I Mr. J. Lycett on Fossil Shells from the 



189. Cardium punctato-striatum ; oblong, transverse; umbones 

 anterior ; anterior side short, rounded, posterior lengthened and ob- 

 liquely truncated, ventral border curved ; striae longitudinal, nume- 

 rous and closely punctated, crossed by obscure numerous encircling 

 lines giving the surface almost a scabrous aspect ; there is likewise an 

 obscure oblique posterior longitudinal keel, posteriorly to which the 

 surface is much more depressed. 



195. Cytherea picta ; suborbicular, rather longer than wide, 

 smooth, moderately convex ; umbones mesial, slightly curved for- 

 wards ; hinge-margin oblique, curved ; ventral border rounded ; sur- 

 face with several broad zones of colours at irregular intervals, the 

 bands being white upon a chocolate-coloured ground ; length ^ inch : 

 rare. 



197. Astarte quadrata ; quadrate, transverse, thick, rugose, lines 

 of growth irregular and strongly marked, forming an angle somewhat 

 rounded upon the posterior side of the shell ; umbones anterior, lunule 

 excavated, cordate. 



198. Astarte bullata ; small, subglobose ; umbones mesial, curved 

 forwards ; lunule excavated, cordate ; costae elevated, broad, rather di- 

 stant, usually, but not always, regular ; size that of duck shot. 



199. Ptychomya Agassizii; new genus indicated, but not described, 

 by M. Agassiz : see a notice of this genus at page 408. 



20 1 . Astarte Menkei ; our specimens do not exhibit the wrinkled 

 surface near to the umbones described by Dunker, but this probably 

 is an inconstant character. 



203. Astarte formosa ; rather depressed, transversely ovate ; um- 

 bones pointed, mesial, inclined forwards ; lunule large, slightly exca- 

 vated ; hinge-line lengthened, oblique ; anterior border rounded, pos- 

 terior rather produced and slightly angulated ; encircling ribs very 

 closely arranged, irregular, small, and little elevated ; length equal to 

 Jths of the breadth. 



205. Cordis aspera; transversely oval, gibbose; umbones large, 

 mesial ; lunule small, cordate ; hinge-line straight, sloping, borders 

 rounded, inner margin toothed ; encircling costse narrow, elevated, 

 rather distant ; interstitial spaces with fine encircling striae. This 

 species approaches near to Corbis Lajoyei, D' Archiac, but the ribs are 

 more elevated and distant, the umbones are larger, and the hinge-line 

 is not so nearly horizontal. 



207. Corbis Icevigatus ; small, transverse, moderately convex ; 

 umbones mesial, lunule small ; hinge-line straight, nearly horizontal ; 

 costae few, widely separated, elevated, the interstitial spaces smooth ; 

 length \ inch, breadth |th more. 



211. Panopcea delicatissima ; small, transverse, oblong, convex ; 

 umbones large, mesial ; hinge-line rather straight ; ventral border 

 lengthened, rather straight ; costae concentric, regular, closely ar- 

 ranged, delicate ; length £ inch : breadth \ inch ; the hinge has not 

 been seen. 



204. Lucina lyrata ; the abundance of this species, its wide diffu- 

 sion and great variety of aspect demand something more than a mere 

 notice of its occurrence. The two extreme varieties are as follows : — 



