PLATE XXVI. 



PENTACEROS PUNCTATUS, n. sp. (Page 88.) 



From the Upper Chalk. 

 FIG. 



1. Abactinal view of remains of arms; natural size. (Coll. Brit. Mus., E. 2-561.) 



a. Lateral view of margin; natural size. 



b. Enlarged view of single ossicle ; magnified 2 diameters. 



PENTACEROS BOYSII, Forbes, sp. (Page 80.) 

 From the Upper Chalk. 



2. Actinal view ; natural size. (Coll. Sedgwick Mus., Cambridge.) 



a. Lateral view of margin ; natural size. 



b. View of isolated ossicle ; magnified 4 diameters. 



MITRASTER COMPACTUS, Forbes, sp. (Page 67.) 

 From the Upper Chalk. 



3. Abactinal view ; natural size. (Willett Coll., Brighton Mus.) 



a. View of end of arm ; magnified 4 diameters. 



b. Lateral view of supero-marginal ossicles ; magnified 4 diameters. 



c. Lateral view of infero-marginal ossicles ; magnified 4 diameters. 



CALLIDERMA MOSAICUM, Forbes, sp. (Page 9.) 

 From the Lower Chalk. 



4. Actinal view of ambulacral groove ; magnified 4 diameters. (Coll. Sedgwick 



Museum, Cambridge.) 



a. Actinal view ; natural size. 



b. Infero-marginal ossicle ; magnified 4 diameters. 



