PLATE XXXVII. 



Froiji the Lower Grey Chalk. 



Fig. 1 a. Sakknia Aus 



] d. 



1 e. 

 1/ 



\h. 

 1 i. 



Fig. 2. 



TEN J, Forbes. Test, natural size. British Museum. 



Under surface, showing peristome magnified two 

 diameters. 



Upper surface, showing disc magnified two dia- 

 meters. 



Lateral view, showing periprocte magnified tM'o 

 diameters. 



Inter-ambulacra, entire, magnified four diameters. 



Ambulacra, do., do. do. 



Single plate of ambulacra, do. six do. 



Single tubercle in profile, do. do. 



Apical disc detached, do. four do. 



Test, natural size, do. do.. Royal 



School of Mines. 



