PLATE VII. 



Figs. 1, 1 a. — Myalina Bedesdalensis. Two views of a cast of a fine specimen 

 from the Carboniferous Limestone of Derbyshire. In the York Museum. 

 (Page 109.) 



Figs. 2, 2 a. — Posidoniella vetusta. Two views of a very fine example from the 

 Limestone of Trey Cliff, Castleton, showing, 2 a, the anterior edge of the shell 

 with the anterior lobe x and the byssal notch. In the Collection of Mr. J. 

 Barnes, of Manchester. (Page 84.) 



Fig. 3. — Myalina peralata. A testiferous example from the Carboniferous 

 Limestone of Settle. In the Collection of the Woodwardian Museum, Cambridge. 

 (Page 119.) 



Fig. 4. — Posidoniella Isevis. A fine pyritised example from the roof of the 

 Bullion seam, Lancashire coal-field. In the Collection of Owens College. 

 (Page 94.) 



Figs. 5 and 6. — Modiola ligonula. Two specimens from the highest bed of 

 the Calciferous Sandstone series, St. Monan's, Fife. My Collection. (Page 69.) 



Fig. 5 a. — Modiola ligonula. Viewed from above. (Page 69.) 



Figs. 7 — 9. — Posidoniella variabilis. From the black shales below the Mill- 

 stone Grits, Todmorden. In the Collection of Owens College. (Page 100.) 



Fig. 10. — Posidoniella subquadrata. A fine specimen from the roof of the 

 Bullion coal, New Hey, near Rochdale. In the Collection of Professor Boyd 

 Dawkins. (Page 101.) 



