PLATE XLVIII. 



DiscoiDEA Favrina, Desor, 1842. 

 From the Upper Greensand. 



Fig. 1 a. Upper surface of a test, natural size. British Museum. (P. 210.) 



b. Base of do. do. do. 



c. Lateral view of do. do. do. 



d. Apical disc, magnified. 



e. Inter-ambulacra, ambulacra, and poriferous zones, magnified four times. 

 /. Portion of the basal plates of the same parts, do. do. 



ff. Inter-ambulacral plates, do. do. 



DiseoiDEA DixoNi, Forbes, 1S50. 

 From the Upper White Chalk. 



Fig. 2 a. Upper surface, magnified two diameters. My collection. (P. 212.) 



b. Lateral view, do. do. 



c. Apical disc, highly magnified. 



d. Inter-ambulacra, ambulacra, and poriferous zones, magnified six times. 

 3 a. Base of another test, magnified two diameters. 



b. Inter-ambulacra, ambulacra, and poriferous zones, magnified eight times. 



