PLATE XXI 



Fig. I. Diplasterias octoradiata, forma eunota, type, Undine Harbour, 

 South Georgia, x 1-4. 



Fig. 2. Same, type, x 1-3. Coelomic side of the skeleton of ray which 

 has been opened along ambulacral ridge and spread out. 



Fig. 3. Diplasterias octoradiata, forma octoradiata, St. MS 10, for com- 

 parison, X 1-3. 



Fig. 4. Diplasterias meridionalis, St. MS 10, xi-3; prepared as figs. 

 3 and 4. 



