PLATE X. 



Fig. 1. — Pterinopecten granosus. A left valve. From the Carboniferous Lime- 

 stone of Kildare. York Museum. (Page 57.) 



Fig. 2. — Pterinopecten granosus. A left valve. From the Carboniferous Lime- 

 stone of Clitheroe. In the Collection of Mr. R. Law. (Page 58.) 



Fig. 3. — Pterinopecten granosus. The left valve of a bivalved example, showing 

 (Fig. 8 a) the differences in the contour of each valve, and (Fig. 3 b) the flattened 

 right valve. From the Carboniferous Limestone of Castleton. My Collection. 

 (Page 58.) 



Fig. 4. — Pterinopecten eximius. A portion of the left valve. From the Car- 

 boniferous Limestone of Derbyshire. In the Woodwardian Museum, Cambridge. 

 (Page 59.) 



Fig. 5. — Pterinopecten eximius. The greater portion of a right valve. From 

 Kniveton Quarry, Derbyshire. My Collection. (Page 59.) 



Fig. 6. — Pterinopecten granosus. Portion of a left valve. Sowerby's type. 

 Preserved in the Sowerby Collection, Natural History Museum, South Kensington. 

 (Page 58.) 



