PLATE 18 

 Tissintia prototypa (Williams) (p. 108) 

 Lower Llanvirn ashy shales, near Llwyn Bedw Farm, Llandeilo, Carmarthenshire. 

 Fig. i. BB 35306. Internal mould of a pedicle valve, x 3. 

 Fig. 2. BB 35307. Latex cast of the exterior of a brachial valve, x 3-3. 



Weston Beds, near Lyde, Shropshire. 

 Figs, ii, 3. BB 35311a, b. Latex cast of the exterior and the internal mould of a pedicle 

 valve, X 1 -9, x 2-4. 



Fig. 6. BB 35315a. Latex cast of the interior of a brachial valve, x 2-5. 



Figs. 8, 7. BB 35314a. Latex cast and internal mould of a brachial valve, x 2-2. 



Weston Beds, near Priestweston, Shropshire. 

 Figs. 5, 4. BB 35312a. Latex cast and mould of the interior of a pedicle valve, x 2-6. 



Weston Beds, near Little Weston, Shropshire. 

 Fig. 9. BB 35313b. Latex cast of the exterior of a brachial valve, x 2. 



Tissintia immatura (Williams) (p. 109) 



Meadowtown Beds, Quinton's Quarry, Shropshire. 

 Fig. 10. BB 35479. Internal mould of a pedicle valve, X27. 



Meadowtown Beds, near Meadowtown, Shropshire. 

 Fig. 12. BB 35477a. Latex cast of the internal mould of a brachial valve, x 2. 

 Fig. 15. BB 35476b. Latex cast of the exterior of a pedicle valve, x 3-8. 



Meadowtown Beds, Minicop Farm, Shropshire. 

 Figs. 13, 14. BB 35474a, b. Latex cast of the exterior and the internal mould of a pedicle 

 valve, x 2, X2-5. 



