PLATE XXXVIII. 



From the Lower Grey Chalk. 



Fig. 1 a. Salenia Clarkii, Forbes. Test, natural size. British Museum. 



\ b. „ ,, Upper surface, showing disc magniHed two diameters. 



1 c. „ „ Under do., do. peristome do. do. 



I d. „ „ Lateral view, showing ambulacral areas and pori- 

 ferous zones, magnified two diameters. 



1 e. „ „ Apical disc detached, magnified four diameters, 



1 /. „ „ Inter-ambulacra entire, do. do. 



I y. „ „ Ambulacra entire, do. do. 



1 h. „ „ One plate and ambulacra, do. six do. 



Fig. 2 a. Salenia, with spines in situ, natural size, Royal School of Mines. 



2 b. „ do. club-shaped, magnified three times, 

 2 c. „ do. spatulate do. do. 



2 d. ,, Base of spine showing Hues, &c., do. six do. 



Figs. 3, 4. ,, Bent spines, magnified three times. 



