PLATE XL. 



From ilip Red Chalk. 



Fig. 1 a. PeltastesWii.tshirei, Wm/ht. Test, natural size. Cabinet of the Rev. T. 



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

 h. ,, „ 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. 



ff- „ „ Apical disc, do. do. 



/'. „ ,, Single plate and portion of ambulacra, mag- 



nified six times. 



Fig. 2. 



Mould magnified two diameters. 



