PLATE XXI B. 



From the Bed Chalk. 



Fig. 1 a. PsEUDODiADEMA Brongniarti, Agassiz. Cabinet of the Rev. T. Wiltshire, 

 F.G.S. (P. 111.) 



1 b. Lateral view of the same. Both natural size. 



Fig. 2. Another specimen, belonging to C. B. Rose, Esq., F.G.S. 



From the Grey Chalk. 



Fig. 3 a. PsEUDODiADEMA Brongniarti, Agassiz. Cabinet of the Rev. T. Wiltshire, 

 F.G.S. 



3 b. The test restored from this fine large specimen. Upper surface. 



3 c. Do. do. do. Under surface. 



3 d. Do. do. do. Lateral view. 



3 e. Portion of the ambulacra, inter-ambulacra and pores, magnified four times. 



