PLATE VIII. 



Nymphaster Coombii, Forbes, sp. (P. 15.) 



From the Lower Chalk. 

 Fio. 



1 a. Actinal aspect of the type specimen ; natural size. (Coll. Brit. Mus.) 

 b. An infero-marginal plate ; magnified 3 diameters. 



Calliderma Smithi^s, Forbes, sp. (P. 6.) 

 From the Loiver Chalk. 



2 a. Profile view of a fragment of a ray ; natural size. (Coll. Brit. Mus.) 



b. Actinal view of the same; natural size. 



c. An adambulacral plate; magnified 6 diameters. 



Ntmphastbr oligoplax, Sladeu. (P. 19.) 

 From the Upper Chalk. 



3 a. Abactinal aspect ; natural size. (Coll. Brit. Mus.) 

 b. A supero-marginal plate ; magnified. 



Ntmphaster maeginatus, Sladeu. (P. 18.) 

 From the Upper Chalk. 



4 a. Abactinal aspect ; natural size. (Coll. Brit. Mus.) 

 b. A supero-marginal plate ; magnified 4 diameters. 



