14 HAWAIIAN AND OTHER PACIFIC ECHINI. 



Chondrocidaris a. Ag. 

 Chondrocidaris gigantea A. Ag. 



Chondrocidaris gigantea, A. Ag. 1803. P.ull. 1^1. C. Z., I, 2, p. IS. Eev. Ech. Tl. la. 



Plate 4, figs. 1,7-19. 



At tlie time a specimen of this species was first obtained from the Ha- 

 waiian Islands, it was separated from the other Cidarida3 as a new genu.s; 

 subsequently it was assigned to tlje genus Phjllacanthus. An examina- 

 tion of two additional specimens collected by the "Albatross" from Station 

 4050 off Kealakekua Light House, W. coast of Hawaii, as well as of other 

 Cidaridte, inclines us to revert to the first determination and to recognize 

 again the genus Chondrocidaris, not merely upon the nature of the pedi- 

 cellai'ite as has been done by Mortensen,' but also owing to the uniform 

 granulation of the test and of the abactinal system. This is composed of 

 very small tubercles of nearly uniform size, carrying minute, triangular, 

 miliary spinelets. 



The abactinal system is circular. There is only a single ring of secondary 

 tubercles round the scrobicular area. 



In a specimen of 83 mm. diameter there are nine and nine primary inter- 

 ambulacral plates. The abactinal system is 31 mm. in diameter; the 

 greatest width of the anal pentagon is 15 nun. ; the actinal system is 19 mm. 

 When dry the secondary spines are at the tip, of a dark chocolate color, and 

 the primary radioles ai-e of the same color from the milled ring to the base 

 of the tip of the radiole. The rest of the spine is of a lighter color. 



The maunnary boss of the primaries is perforate, but not crenulated. 



No large globiferous pedicellaria3 are present in any available specimens, 

 so that it lias not been possible to determine the accuracy of Mortensen's 

 figures. 



Tlie tridentate pedicellarioe (PI. 4, figs. I'/, 17-19) have the valves very 

 slender and in contact for practically their entire length. They are about 

 1.65 mm. long, while the stalk is somewhat shorter. They are rather 

 infrequent, occurring chiefly between the actinal primary spines. 



The small globiferous pedicellarias (Pi. 4, figs. /.?, 77. I/;) are very char- 

 acteristic. The valves are short and wide with a large opening, well- 

 defined lip and prominent end-tooth. They are only .40 nun. in length, and 



1 Ingolf Echinoidea, 1903, Pt. I, p. 29. 



