PLATE XXV. 



Spilera (continued). 



Figs. 

 1, 2. 8. corrugata, Sow. Lower Greensand, Atherfield. (P. 157.) 



1. Crackers, Atherfield. Sedgwick Museum. Right valve. 



2. Perna-bed, Atherfield. British Museum, No. 50349. Hinge of right valve, x f. 



3. 8. sp. Base of Chalk Marl, Chard. Museum of Practical Geology, No. 

 7899. a, right valve; b, dorsal view. (P. 159.) 



Gen us — Mutiella, Stoliczka. 



4—6. M. ? canaliculata (Sow.). Upper Greensand, Blackdown. Sedgwick 

 Museum. (P. 1G0.) 



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



5 a, left valve, x 1 \ ; b, anterior view of same, x 1 h ; c, hinge, X 2. 



6 a, right valve ; b, anterior view of same; c, hinge, x 2. 



Gen us — Unicarditjm, d'Orbigny. 



7. U. claxbiense, Woods. Claxby Ironstone, Benniworth Haven. Sedgwick 

 Museum, a, left valve; b, dorsal view of the same. (P. 162.) 



8-11. U. ve dense, Woods. Lower Greensand (Crackers), Atherfield. Sedgwick 

 Museum. (P. 163.) 



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



9. Left valve. 

 10. Hinge of right valve, x H. 

 11a, right valve ; b, anterior view. 



12. U. sp. Upper Greensand, South Devon. Museum of the Geological 

 Society, No. 1580. a, right valve; b, dorsal view; r, portion near 

 the middle of the anterior half, X 8. (P. 163.) 



13, 14. U. ringmeriense (Mant.). Base of Chalk Marl. (P. 164.) 



13. Titherleigh. Sedgwick Museum. Left valve. 



14. Chardstock. Museum of Practical Geology, No. 19803. a, right valve ; b, 



dorsal view. 



Genua — Thetironia, Stoliczka. 



15. T. minor (Sow.). Lower Greensand (Crackers), Atherfield. Sedgwick 

 Museum. 15a, right valve; b, portion near the mid-ventral margin, 

 X 6 ; r, portion near the postero-clorsal margin, X 6. (P. 167.) 



