PLATE XVII. 

 METOPASTER MANTELLI, Forbes, sp. (Page 38.) 



From the Upper Chalk. 

 FIG. 



1. Actinal aspect; natural size. (Coll. Brit. Mus., 40402.) 

 a. Infero-marginal plate ; magnified 4 diameters. 



MITRASTER COMPACTUS, Furbps, sp. (Page 67.) 

 From the Upper Chalk. 



2. Actinal aspect ; copied from Forbes in Dixon's ' Geology of Sussex,' pi. xxu, 



%. 3. 



COMPTONIA COMPTONI, Forbes, sp. (Page 69.) 

 From the Upper Greensand. 



3. Actinal aspect; natural size. (Coll. Brit. Mus., 34311.) 



a. Infero-marginal plate; magnified 3 diameters. 



b. Lateral view of interbrachial arc ; natural size. 



COMPTONIA ELEGANS, Gray. (Page 71.) 

 From the Upper Greensand. 



4. Abactinal view ; natural size. (Coll. Brit. Mus., E. 2567.) 

 a. Actinal view of same specimen ; natural size. 



