PLATE XXIII. 



From the Upper White Chalk. 



1 a. Cyphosoma Konigi, Mantel! . 



Upper surface, natural size. (P. 131.) 



1 b. 



Under surface, natural size. British Museum. 



1 c. 



Lateral view, do. 



1 d. 



Upper part of anibnlacral area, magnified three 





times. 



1 ^• 



Portion of the areas and [)ores, magnified three 





times. 



1/ 



Boss and mammillon, highly magnified. 



1 9- 



Inferior portion of an ambulacrum, magnified 





three times. 



Pig. 2 a. Cyphosoma granulosum, Goldfuss. Upper surface, natural size. (P. 1.29.) 

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



Musemn. 



2 c. „ „ Lateral view, showing the depression 



of the upper surface. 



2 d. „ „ Portion of the areas and pores, magnified 



four times. 



Fig. :3. Cyphosoma Konigi, Maniell. Elevated variety. British Museum. 



