PLATE IX. 



PiCNASTEE ANGUSTATUS, Fovhes, sp. (Page 21.) 



From the Upj^er Chalk. 

 Fia. 

 la. Abactinal aspect ; natural size. (Coll. Brit. Mus.) 



b. Lateral view of the margin ; natural size. 



Metopaster Parkinsoni, Forhea, sp. (Page 31.) 



From the Ujyper Chalk. 



2a. Actinal aspect; natural size. (Coll. Brit. Mus.) 

 h. Lateral view of the margin ; natural size. 



c. An infero-marginal plate ; magnified. 



Mitrastee HuNTERi, Fovbes, sp. (Page 59.) 



From the Upper Chalk. 



3 a. Abactinal aspect of a small example with four supero-marginal plates ; 

 natural size. (Coll. Brit. Mus.) 

 h. Actinal aspect of the same ; natural size. 



c. Lateral view of the margin ; natural size. 



d. A supero-marginal plate ; magnified. 



e. An infero-marginal plate ; magnified. 



