118 HAWAIIAX AND OTHER PACIFIC ECHINI. 



Centrostephanus coronatus A. Ag. 



Echinodiadema coronata Verrill, 1867. Trans. Conn. Acad., I, p. 295. 

 Centroatephanua corouatua A. Agassiz, 1872. Rev. Ech., Pt. I, p. 97. 



Plate 51, figs. 1^-20. 



As this is one of the very few species of DiadematiiljB, whose pedicella- 

 riae have not been examined by Mortensen, we have given figures of them, 

 since they are very different from those of the other species in the genus. 



The fflohiferotis pedicellariiB (figs. 16, 17) are very abundant and are strik- 

 ingly characteristic, because of the conspicuous, nearly globular, deep purple 

 glands on the valves. The latter (figs. 18, 19) are remarkably small, only 

 .12-18 mm. in length, and decidedly curved. The blade is very short, con- 

 cave on its inner face, and terminates in 4 very long, sharp teeth. The stalk 

 (fig. 20) is greatly expaatled at the tip, which is distinctly concave. The 

 organic covering of the stalk is prettily spotted with pigment cells (figs. 

 16, 17). At the top of the stalk, glands are often but not always present. 



The slender tridentate pedicellariae (fig. 12) are very rare and are found 

 only on the abactinal surface. The valves are a trifle over a millimeter long 

 and the stalk is little longer. The blades are narrow and compressed and 

 are in contact for nearly one-half their length. The margins are irregularly 

 serrate. 



The stout tridentate pedicellariae (fig. 13) are common on all parts of the 

 test and vary greatly in size. The valves range from .40 to 1.75 mm. in 

 length. They are decidedly curved, with short wide blades, in contact only 

 at the tip. The margins carry few or no teeth, but the tips are strongly 

 serrate. The stalk scarcely equals the valves in large examples, but may be 

 much lono-er in small ones. 



The ophiccphalous pedicellarias (fig. H) seem to be all of the glandless 

 type. They are abundant everywhere, but especially on the actinal surface. 

 The valves are rather short and blunt, only .30-40 nun. in length. 



The triphj/llous pedicellarite (fig. 15) are common, and are noticeable 

 because of the scattered pigment cells which adorn the organic covering of 

 the stalk and the neck. The latter is considerably thicker than the stalk, 

 while the diameter of the head is only a little greater. The valves are only 

 .20-.30 mm. long, and are wider in proportion to their length than in the 

 other species of the genus. 



