PLATE XVI 1 1. 



Oi'is {continneil). 

 Figs. 



1. <>y(/.v liiihluiiriisis, Woods. Upper GreensaiHl, Ihildiin. I)iiti,-li .Museiiiii, 

 Xo. 1, 171 1-1. <i, oxterioi' ; //, interior oF rit^lil valvr; '■, ])u.-^t(,'ri()i' view 

 of the .same; (/, anterior view. (P. 1 IW.) 



(It'll us: — Cakuita, Jlniijiiieri'. 

 2-4. 0. ? fenesLfidd (Forbes). Lower Green.san(l (/''/-/(((-hed), Alliertield. 

 (P. 12L) 



2. Museum of Practical Geology, No. 14360. a, left valve; 6, dorsal view, x \\\ 



c, muJiau part of left valre, x -1. 



3. Sedgwick Museum. Eight valve, x l{. 



4. Sedgwick Museum, a, left valve; h, auteriur view. 



5. ('. iipiriirriisis, Woods. Lower Greeusand, I'pware. Sedi;\viek ]\Inseuni. 

 ti, ri_i>'lit valve; h, dorsal view; c, tmterior view; </, part near tlic 

 middle of the rio'ht valve, X !■. (P. 12'^.) 



(■». ^'. sp. Lower Greeusand (iV'r;/''-l)ed), Atherlield. Si'd^'wick .Mu.>euin. 

 a, left valve; /j, dorsal view; c, part near the middle of left valve, 

 X 5. (P. 123.) 



7-li. ('. leiiuicu>ittt (Sow.). Gaidt, f'olkestone. 7-P'). Sedj^'wiek Museum. 

 14. British Museum, No. 481:35. (P. 121.) 



7. Left valve, x 1^ 



8 a, left valve ; /*, a-utcriur view. 



9. Right valve. 



10 o, left valve; 6, dorsal view ; c, part near tin' iiiid-vuutTal linrder, X ti. 



11 (T, right v.dve, X Ij ; h, dorsal view, X H ; c, part uear the iiiiildle of the rii;ht 



valve, X 6. 



12. Left valve, x 2. 



13. Inflated variety, a, right valve ; h, dorsal view. 



14. Shoi't and mucli inflated variety. ", right valve : h, dorsal view. 



K), Ki. C. Ootlnl,rnui,d\)v\K Chloritie .Marl. (I*. 12(i.) 



15. Toller Fratruni. Museum of Practical Ueology. No. 14348. Eight valve. 

 It). Chard. O.xford Museum, k, left valve ; //. dorsal view. 



17,18. C. ca ncelldtii, Wooil^. ('halk Rock, Cuekliamsley. Sedgwick i\liiseum. 

 (P. 127.) 



17 If, wax cast of right valve, x Ij ; h, oruameutatiou near the middle of the 



right valve, x 5. 

 18. Natural internal cast. t(, left valve; h, anterior view. 



