PLATE XX. 



Figs. 1 — 3. — Protoschizodus subtruncatus. Three very imperfect examples 

 from the upper beds of the Carboniferous Limestone, Park Hill, Derbyshire. 

 My Collection. (Page 248.) 



Fig. 4. — Protoschizodus subtruncatus. The type specimen of M'Coy's Am/phi- 

 desma subtruncata, from Millicent, co. Cork. In the Griffith Collection, Museum 

 of Science and Art, Dublin. (Page 248.) 



Fig. 5. — Protoschizodus sequilateralis. A fine testiferous specimen from the 

 Magazine Limeworks, Pathhead. In the Collection of the Geological Survey of 

 Scotland. (Page 246.) 



Fig. 6. — Protoschizodus frag ills. The type specimen of Lcptodomus fragilis, 

 M'Coy. In the Griffith Collection, Museum of Science and Art, Dublin. 

 (Page 250.) 



Fig. 7. — Protoschizodus sequilateralis. The type specimen, very imperfect, of 

 Dolabra sequilateralis, M'Coy, from the Carboniferous shale of Doorin, co. Donegal. 

 In the Griffith Collection of the Museum of Science and Art, Dublin. (Page 246.) 



Fig. 8. — Protoschizodus fragilis. A right valve from the Redesdale Ironstone 

 beds, Redesdale. My Collection. (Page 250.) 



Fig. 9. — Protoschizodus fragilis. A young example with the shell partially 

 preserved, from the Carboniferous Limestone of Limerick. In the Collection of the 

 Geological Survey of Ireland. (Page 250.) 



Fig. 10. — Protoschizodus sequilateralis. A somewhat imperfect bivalve example 

 from the Carboniferous Limestone of Clonmel. In the Collection of Mr. J. 

 Wright. (Page 246.) 



Fig. 11. — Protoschizodus sequilateralis. A cast of the right valve from the 

 Limestone of Monaster. Same Collection. (Page 246.) 



Fig. 12. — Protoschizodus sequilateralis. A bivalve example from Burn Anne, 

 Scotland. In the Collection of the Geological Survey of Scotland. (Page 246.) 



