PLATE VIII. ' 



UlNTACRINUS SOCIALIS. DeTAIL OF SlAB I, PHOTOGRAPHED ABOUT .58 NATURAL SiZE. 



The different Specimens may be located by Reference to the marginal 

 Letters and Figures. 



A 3 and A 5. At these points may be seen some very slender pinnules from almost the 

 distal end of arms, adhering to calyx plates of the specimens on which 

 they lie. 

 At these points also are seen parts of arms of a large specimen preserved to 

 a length of 60 era. 



B 1. Large dicyclic specimen, with small but perfectly developed infrabasals. 



B 7. Ventral side of outspread arms and pinnules, belonging to a calyx almost 

 entirely embedded in the slab ; the distal end of the anal tube is visible, 

 but hard to distinguish on the photograph, being so near the color of the 

 adjacent material. 



C 3. Specimen with disk exposed. The anal tube is flattened upon itself into a 

 rather shapeless mass which does not show well in the photograph. The 

 ambulacra may be indistinctly seen. The arms are spread, exposing the 

 ventral side of both arms and pinnules with absolute perfection. 



C 4. A monocyclic specimen, giving a fine view of the dorsal side of arms, and 

 fixed and lower free pinnules. 



D 2. This specimen also gives an excellent dorsal view of the fixed and proximal 

 free pinnules. 

 (In the last four specimens the pinnules can be seen and studied in almost 

 every conceivable position and exposure.) 



D4. Large monocyclic specimen. Both this and B 1 exhibit a great multiplica- 

 tion of interbrachial plates. 



D 6. Small specimen with indistinct base, but showing the arms unusually well. 

 By comparison of the brachials of this specimen and those of C4, D2, and 

 J) 4, the relative size and proportions of these plates in specimens of 

 various stages of growth may be thoroughly studied. 



