PI. ATM XXVI. 



TllKTllJoMA ((■(illliliilC(l). 



Figs. 



1-8. 7'. iibliiiir (Sow.), liower Greensaml. Sedj^'wick Museum. 1-5, Crackers, 

 Atherfielcl. (I, near At her field. 7, 8, Ferruginou-s roek, Shanklin. 



(P. ir,7.) 



1. Right valve. 



2 a, ri<?ht valve ; b, aiiferinr view. 



3. Eij^lit valve. 



4 «, left valve ; h, doi'sal view. 



5. Left valve. 



6. Internal cast of rii;lit valve. 



7. Internal east. ((, left valve ; li, tlursal view. 



8. Internal east of rii^'lit valve. 



9-14. T. hvvhjida (Sow.). Upper Greensand, Blaekduwu. (P. I(i0.) 



9. Sedi,'wiek Museum. Left valve. 



10. Sedgwick Museum, a, right valve; h, hinge of left valve of the same specimen, 



X li. 



11. Museum of Practical Geology, No. 19783. Dorsal view. 



12. Sedgwick Museum. Left valve. 



13. Museum of Practical Geology, No. 19780. a, right valve; //, jiorlidu near 



the posterior margin, x G. 

 \\. Sedgwick Museum. Hinge of right valve, x Ij. 



(JtliUH TjiLLIX.V, Jjili lUVUH. 



15, l(i. T. Carteroni, d'Ovh. Lower Greensand (Crackei's), .Vtlicrfield. Sedywick 

 Museum, Cambridge. (P. 171.) 



15 a, I'ight valve; h, portion near the anterior margin, x 3; c, portion near the 



posterior margin, x 3. 

 10 a, left valve ; h, dt)rsal view of the same ; c, hinge of the same, x li. 



17. '/'. sj). Lower Greensand (Crackers), Atlierfield. Sedgwick Museum. 

 Right valve. (P. 1 72.) 



18, P). T. striatitloides, Utol. Upper Greensand, Blackdown. (P. 172.) 



18. Sedgwick Museum, k, left valve; 6, posterior part, x 3. 



19. Sedi^wick Museum. Interior of riiiht v;ilve. 



