PLATE XL. 



From the Red Chalk. 



Fig. 1 a. PeltastesWii.tshirei, Wright. Test, natural size. Cabinet of the Rev. T. 



Wiltshire, F.G.S. (P. 161.) 

 b> » „ Upper surface, magnified two diameters. 



c. ,, „ Under surface, do. do. 



d. „ „ Lateral view, do. do. 



e - „ „ Inter-ambulacral area, magnified four times. 



/• „ ,, Ambulacral area, do. do. 



g- „ „ Apical disc, do. do. 



I'- „ „ Single plate and portion of ambulacra, mag- 



nified six times. 



Pig- 2. „ „ Mould magnified two diameters. 



