PLATE XVIII. 



Figs. 1 — 5. — Naiadites carinata. A series of casts showing; the muscle-scars 

 and line of the mantle, and the variation of contour. From the roof of the Hard 

 Mine Coal, Adderley Green, North Staffordshire. My Collection. (Page 138.) 



Figs. 4 and 5. — Naiadites carinata. Testiferous examples from the same 

 locality. My Collection. (Page 138.) 



Figs 7 — 9. — Naiadites carinata. Casts from the Stanley Main Seam, 

 Wakefield. My Collection. (Page 138.) 



Figs. 10, 11, and 15. — Naiadites carinata. Young examples from the roof of 

 the Hard Mine Coal, Adderley Green, North Staffordshire. My Collection. 

 (Page 138.) 



Fig. 12. — Naiadites carinata. An obese form from the same locality. My 

 Collection. (Page 138.) 



Figs. 13, 14. — Naiadites carinata. Two views of a very obese form showing 

 the much-wrinkled periostracum. Same locality. My Collection. (Page 138.) 



Fig. 15. — Naiadites carinata. A testiferous specimen of moderate growth. 

 Same locality. My Collection. (Page 13S.) 



Fig. 16. — Naiadites carinata. An aberrant form from the same locality. In 

 the Collection of John Ward, Esq., F.G.S., of Longton. (Page 138.) 



Fig. 17. — Naiadites quadrata. A large compressed form from the roof, Hard 

 Mine Coal, North Staffordshire. My Collection. (Page 140.) 



Figs. 18 and ]9. — Naiadites quadrata. Crushed examples from the Burnwood 

 Ironstone, Fenton. My Collection. The artist has drawn this shell with its 

 anterior side uppermost. (Page 140.) 



Fig. 20. — Naiadites quadrata. A crushed testiferous example from above the 

 Woodhead Coal of Froghall. My Collection. (Page 140.) 



Figs. 21, 23 — 25. — Naiadites quadrata. Uncrushed examples from the roof of 

 the Hard Mine Coal, Adderley Green, North Staffordshire. My Collection. 

 (Page 140.) 



Fig. 22. — Naiadites elongata. From the Ironstone Band in the Middle Coal- 

 measures of the Lancashire Coal-field, Prestolee. (Page 142.) 



Figs. 2G — 35. — Naiadites elongata. A series from the Knowles Ironstone of 

 Fenton Park, North Staffordshire, figs. 31 and 32 being the type forms. 

 (Page 142.) 



