14 HAWAIIAN AND OTHER PACIFIC ECHINI. 



ClIONDROCIDARIS A. Ag. 



Chondrocidaris gigantea A. Ag. 



Chondrocidaris gigantea, A. Ag. 18G3. Bull. M. C. Z., I, 2, p. 18. Rev. Ech. PI. la. 



Plate 4, figs. 13-19. 



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

 waiian Islands, it was separated from the other CidaridaB as a new genus; 

 subsequently it was assigned to the genus Phyllacanthus. An examina- 

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

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

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

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

 cellariae as has been done by Mortensen/ but also owing to tlie uniform 

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

 very small tubercles of nearlj^ uniform size, carrying minute, triangular, 

 miliary spinelets. 



Tlie 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 mm. ; the actinal system is 19 mm. 

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

 the primary radicles are 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 mammary boss of the prinuiries is perforate, but not crenulated. 



No large globiferous pedicellaria) are present in any available specimens, 

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

 figures. 



The tridentate pedicellaria; (PI. 4, figs. /.^, 17-19) have the valves very 

 slender and in contact for ])ractically their entire length. Tliey are about 

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

 infrequent, orcurrinLi" chielly between the actinal primary spines. 



The small globiferous pe(licellaria> (PI. 4. figs. 7J, 7J, 16) are very char- 

 acteristic, l^he valves are short and wide with a large opening, well- 

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



» lujiolf Kchiiioidfa, ia03. Pt. I, \\ 29. 



