PLATE XX. 



PENTACEEOS BULBIFERUS, Forbes, sp. (Page 77.) 



From the Upper Chalk. 

 FIG. 



1. Abactinal view; natural size. (Coll. Brit. Mus., 40175.) 



a. Plate from dorsal part of disc ; magnified 3 diameters. 



b. Supero-rnarginal plate ; magnified 3 diameters. 



c. Plate from dorsal part of disc ; magnified 2 diameters. 



2. Abactinal view of two specimens ; natural size. (Coll. Brit. Mus., 48748.) 



a. Madreporite ; magnified G diameters. 



b. Proximal supero-marginal plate ; magnified 4 diameters. 



