PLATE XXI. 



Pentaceeos bulbiferus, Forbes, sp. (Page 77.) 



From the Upper Chalk. 



Fig. 



1. View of the extremities of three arms and portion of disc ; natural size. 

 (Coll. Brit. Mus., E. 5040.) 



a. Ventro-lateral plate; magnified 6 diameters. 



h. Actinal view of the extremities of two of the above arms ; natural size. 



Pentagonaster bobustus, n. sp. (Page 73.) 



From the Upper Challi. 



2. Abactinal aspect; natural size. (Coll. Brit. Mus., 48085.) 

 a. Lateral view of an arm ; natural size. 



Pentaceros BULisiFEKUs, Forhes, sp. (Page 77.) 

 From the U})per Chalk. 



o. Abactinal aspect ; natural size. (Coll. Brit. Mus., E. 5041 .) 



a. Madreporite ; magnified G diameters. 

 4. Abactinal aspect ; natural size. (Coll. Brit. Mus., 40399.) 



a. Madreporite; magnified G diameters. 



