PLATE XXIII. 



From the Upper White Chalk. 



Fig. 1 a. Cyphosoma Konigi, Mantell. Upper surface, natural size. (P. 131.) 



1 b. „ „ Under surface, natural size. British Museum. 



1 c. „ „ Lateral view, do. 



1 d. „ „ Upper part of ambulacral area, magnified three 



times. 

 1 e. ,, „ Portion of the areas and pores, magnified three 



times. 

 1/. „ „ Boss and maramillon, highly magnified. 



1 fj- „ „ Inferior portion of an ambulacrum, magnified 



three times. 



Pig. 2 a. Cyphosoma granulosum, Goldfass. Upper surface, natural size. (P. 129.) 



2 b. „ „ Under surface, natural size. British 



Museum. 

 2 c. „ „ Lateral view, showing the depression 



of the upper surface. 

 2 (J. „ „ Portion of the areas and pores, magnified 



four times. 

 Fig. 3. Cyphosoma Konigi, Mantell. Elevated variety. British Museum. 



