PLATE XXVIII. 



Drom the Upper White Chalk. 



Fig. ] a. Cyphosoma spatui,ifektjm, Forbes. Test, natural size. British Museum. 



(P. 141.) 



1 b. ,, „ Upper surface of do., magnified twice. 



1 c. „ „ Under surface of do., do. do. 



1 d. „ „ Lateral view of do., do. do. 



1 e. „ „ Inter-ambulacral plates, do. six times. 



1 /. ,, „ Ambiilacrum entire, do. do. 



1 ff. „ „ Inter-ambulacral plates, do. do. 



1 h. ,. „ Lower portion of an ambulacrum, mag- 



nified six times. 



