660 BXPLANAHOlf OF THE 7LA.TI:B. 



Fig. B. Pexiiwwra infemalis, showing the disk and the variations of 

 the " naked plates," X 3. 

 C. OpUopvmx stellatus, showing the arrangement of the radial 

 and interradial plates on the disk, x 2. 



Plate IX. 



Pig. A. Ciuyumaria semperi, 



B. Colochirus tuherculosus, Spicules seen from the side and 



from below. 



C. Actinocummis difftcilis. 



D. Thyone oTceni. Calcareous ring and oesophagus. 



E. a and 6, spicules of Sfereoderma vdlidum; c, d, the same, 



seen a little out of focus; e, a smaller spicule ; /, a spicule 

 seen in side view. 



F. Phyttophorus proteus. F'. Farts of calcareous ring. 



G. Holothuria macleari. 



AU. but figs. D and F' are magnified 220 times, and are figures of 

 spicules; D is magnified f, F' twice. 



Plate X. 



Fig. A. Antedon carpenteri, nat. size. A a, A &, A c. First, second, 

 and typical pinnules, X 3. 



B. pwmila, X 3. B a, B 5. First and fourth pinnules, 



X3. 



C. hveni, nat. siee. C a, C 5, C c. First, third, and typical 



pinnules, x 3. Gd,Ce, Dorsal surface of arms in regions 

 marked x and ^ in C, X 3. 



Plate XI. 



Fig. A. Antedon bidens, x2. A a. A cirrus, x4. A J, Ac. First 

 and third pinnules, x 4. 



B. decipiera, xf. Ba, Arm-joints from above, x4. 



