PLATE XV. 



Figs. 1, 3. — Aviculopecten clathratus. A left valve. From Little Island, Cork. In the Collection 

 of Mr. J. Wright. (Page 82.) 



Fig. 2. — Aviculopecten clathratus. A left valve. From Castleton, Derbyshire. My Collection. 

 (Page 82.) 



Fig. 4. — Aviculopecten clathratus. A right valve of a very young specimen. Mr. J. Wright's 

 Collection. (Page 82.) 



Fig. 5. — Aviculopecten clathratus. A left valve of the above shell. (Page 82.) 



Fig. 6. — Aviculopecten clathratus. A right valve. Same locality. In the Collection of the 

 Geological Survey of Ireland. (Page 82.) 



Fig. 7. — Aviculopecten clathratus. The type of M'Coy's Pecten inter costatus. In the Griffith 

 Collection, Museum of Science and Art, Dublin. (Page 83.) 



Fig. 8. — Aviculopecten planoclathratus. A left valve. From Little Island, Cork. In the Col- 

 lection of Mr. J. Wright. (Page 92.) 



Fig. 9. — Aviculopecten planoclathratus. A right valve. Same locality and Collection. (Page 92.) 



Fig. 10. — Aviculopecten planoclathratus. A left valve. From Castleton, Dei'byshire. My Col- 

 lection. (Page 92.) 



Fig. 11. — Aviculopecten planoclathratus. A left valve. From Poolvash, Isle of Man. My Col- 

 lection. (Page 92.) 



Fig. 12. — Aviculopecten planoclathratus. M'Coy's type. In the Griffith Collection, Museum of 

 Science and Art, Dublin. (Page 92.) 



Fig. 13. — Aviculopecten pera. A right valve. From Narrowdale, Staffordshire. My Collection. 

 (Page 78.) 



Fig. 14. — Aviculopecten pera. A left valve. From Wetton. In the Collection of the Geological 

 Survey, Jermyn Street. (Page 78.) 



Fig. 15. — Aviculopecten pera. A left valve. From Narrowdale. My Collection. (Page 78.) 



Fig. 16. — Aviculopecten perradiatus. A left valve. From Park Hill, Derbyshire. My Collection. 

 (Page 87.) 



Fig. 17. — Aviculopecten perradiatus. A left valve. From Narrowdale. Museum of the Geological 

 Survey, Jermyn Street. (Page 87.) 



Fig. 18. — Aviculopecten perradiatus. The cast of a right valve. From Park Hill. My Collection. 

 (Page 87.) 



Fig. 19. — Aviculopecten intermedins. A left valve. From the Carboniferous Limestone of Hill 

 Bolton. My Collection. (Page 81.) 



Fig. 20. — Aviculopecten intermedins. A left valve. From Poolvash, Isle of Man. My Collection 

 (Page 81.) 



Fig. 21. — Crenipecten semicircularis. A left valve. From Castleton, Derbyshire. In the Col- 

 ection of Mr. R. Law. (Page 113.) 



Fig. 22. — Crenipecten semicircularis. A right valve showing the peculiar hinge-plate. Lunedale. 

 My Collection. (Page 113.) 



Fig. 23. — Crenipecten semicircularis. A right valve. From Derbyshire. Wood Collection, York 

 Museum. (Page 113.) 



Fig. 24. — Aviculopecten intermedins. A left valve, showing the long posterior ear. From Settle. 

 In the Woodwardian Museum. (Page 81.) 



Fig. 25. — Aviculopecten intermedins. A specimen from Castleton, which I think may be the adult 

 form. My Collection. (Page 81.) 



