PLATE XVII. 



Fig. 4 l. — Schizodus axiniformis. A cast from the Redesclale Ironstone. My 

 Collection. (Page 219.) 



Fig. 2. — Schizodus axiniformis. The cast of an adult example from the 

 Pennystone Ironstone, Coalbrookdale. My Collection. (Page 219.) 



Fig. 3. — Schizodus axiniformis. A cast from the Redesclale Ironstone. My 

 Collection. (Page 219.) 



Fig. 4. — Schizodus axiniformis. A young example. Same locality. My 

 Collection. (Page 219.) 



Fig. 5. — Schizodus axiniformis. Showing portion of the hinge in the right 

 valve. Same locality. My Collection. (Page 219.) 



Fig. 6. — Schizodus axiniformis. Showing the hinge of a left valve. Same 

 locality. My Collection. (Page 219.) 



Fig. 7. — Schizodus carbonarius. The type specimen of Sowerby's Venus 

 carbonaria. From the Pennystone Ironstone, Coalbrookdale. In the British 

 Museum (Natural Hist.), Geological Department. (Page 222.) 



Fig. 7 a. — Schizodus carbonarius. The same specimen viewed from above. 

 (Page 222.) 



Fig. 8. — Schizodus carbonarius. A fairly perfect specimen. From the same 

 locality. My Collection. (Page 222.) 



Fig. 8 a. — Schizodus carbonarius. The anterior aspect of the same specimen. 

 (Page 222.) 



Fig. 9. — Schizodus carbonarius. A very large and perfect example from the 

 same horizon. In the Woodwardian Museum, Cambridge. (Page 222.) 



Fig. 10. — Protoschizodus axiniformis. The type of Amphidesma axiniformis, 

 Portlock. In the Museum of the Geological Survey, Jermyn Street. (Page 228.) 



Fig. 11. — Protoschizodus axiniformis, var. depressus. The type of Amphidesma 

 carbonaria, Portlock. In the same Collection. (Page 232.) 



Fig. 12. — Protoschizodus axiniformis, var. depressus. The type of Amphidesma 

 carbonaria, var. depressa. In the same Collection. (Page 232.) 



Fig. 13. — Protoschizodus axiniformis. The type of Amphidesma deltoidea, 

 Portlock. In the same Collection. (Page 228.) 



Fig. 14. — Protoschizodus axiniformis. The cast of both valves, showing 

 muscle-scars and pallial line. From one of the Lowick Limestones. In the 

 Woodwardian Museum, Cambridge. (Page 228.) 



Fig. 15. — Protoschizodus impressus. A specimen from Tournay, Belgium. 



Fig. 15 a. Showing the hinge-teeth of the left valve. (Page 234.) 



Fio-. 16. — Protoschizodus axiniformis. A left testiferous valve. From the 

 Redesclale Ironstone. My Collection. (Page 228.) 



Fig. 17. — Protoschizodus axiniformis. A perfect example. From the Redes- 

 dale Ironstone, Bellingham. My Collection. (Page 228.) 



Fig. 17 a. — Protoschizodus axiniformis. The same specimen viewed from 

 above. (Page 228.) 



Fig. 18. — Protoschizodus axiniformis. A perfect example. From the Upper 

 Limestone series, Garngad Road, Glasgow. In the Collection of Mr. James 

 Neilson. (Page 228.) 



Fig. 19. — Protoschizodus axiniformis. The cast of a full-sized shell. From 

 the Upper Limestone series of Kewfield, Scotland. (Page 228.) 



