PLATE XXV. 



Si'H.EiiA (continued). 



Figs. 

 1, 2. S. cnrnKjiifii, Sow. Lower Greensand, Atherfield. (P. L57.) 



1. Crackers, Atli(>rfi('lil. Sedi^'wick Museum. Right valve. 



2. P^rHn-becl, Atlierfic'lcl. Brit isli Museum, No. 60349. Hinge of right valve, x |. 



•3. .9. s]i. TiasG of Chalk Marl, Chard. IMu.'^enm of Practical Geology, No. 

 78V)9, It, right valve; //, dorsal view. (P. 159.) 



Gmufi — MuTiELL.v, Sinliczica . 



4'-G. M. ? rrniiiliritltda (Sow.). Upper Greensand, Blackdown. Sedgwick 

 Mnseiim. (P. 160.) 



4 a, left valve ; h, interior of same ; c, dorsal view ; d, portion of anterior part, x 4. 



5 a, left valve, x H ; h, anterior view of same, x \\ ; c, hinge, x 2. 

 T) ((, right valve ; h, anterior view of same ; c, hinge, x 2. 



G finis — Unic.\rdium, (VOrhhinii. 



7. p. claxlnrnsp. Woods. Claxby Ironstone, Benniworth Haven. Sedgwick 

 Museiun. n, left valve; h, dorsal view of the same. (P. 1(V2.) 



8-1 L J"^. rPctense,'^ooi\fi. Lower Creen sand (Crackers), Atherfield. Sedgwick 

 Museum. (P. 1G3.) 



8 a, left valve ; h, dorsal view ; c, portion near the mid-ventral margin, x 3. 



0. Left valve. 

 10. Hinge of right valve, x li. 

 11 a, right valve ; h, anterior view. 



12. IL sp. Upjwr Greensand, South Devon. Museum of the Geological 

 Society, No. 1 580. a, right valve ; h, dorsal view ; r, portion near 

 the middle of the anterior half, X 8. (P. 16;3.) 



13, 14. r. riniiuurJpni<r (Mant.). Base of Chalk Marl. (P. IGl.) 



l;r TithcrliMgh. Sedgwick Museum. Left valve. 



14. Chardstock. Museum of Practical Geology, No. 19803. a, rigJit v:ilve ; b, 

 dorsal view. 



GrnvK — T 1 1 KTT RONi .\ , SftiJicdTi . 



1-5. T. mivor (Sow.). T/Ower Greensand (Crackers), Atherfield. Sedgwick 

 Museum. }T)(i, right valve; /;, portion near the niid-venlral margin, 

 X 0; r, portion near the postt^ro-dorsal margin, X •>. (!'. 1G7.) 



