STEPHANOCIDAIIIS HAWAIIEXSIS. 19 



diameter, the largest radiolos are 83 mm. long, with six and six primary 

 interambulacral tubercles. In a specimen 20 mm. ir. diameter with six 

 and six primary tubercles, the longest radiole measures 56 mm. In a 

 specimen 32 mm. in diameter with six and seven primary tubercles, the 

 abactinal system is 15 mm., the anal system 10 mm., and the actinal 13 

 mm. in diameter. In a specimen 31 mm. in diameter, the longest radiole 

 measures 73 mm. In a specimen 14 mm. in diameter with five and five 

 primary tubercles, the longest radiole is 34 mm., and the abactinal as well 

 as the actinal system, 6 mm. 



In a small specimen 9 mm. in diameter, with five and four primary 

 interambulacral plates, the abactinal system measures 4 mm., the anal 

 svstem 2.5 mm., and the lono-est radiole 16 mm. 



In this small specimen the genitals are in contact at the proximal angles; 

 the ocular plates do not as yet separate them as they do in larger specimens 

 (PI. 26, fig. 1) where the ocular and genital plates form a continuous ring 

 in contact with the distal row of large anal plates. The anal plates form 

 four or five irregular rows of large plates diminishing in size towards the 

 anal opening. The primary radioles are flattened on the lower side (PI. 24), 

 rounded above (PI. 25) ; they vary greatly in color. Most of them are 

 transversely banded with brick-red and yellowish or white, from the tip 

 of the radiole to the dark, chocolate-colored band above the milled ring. 

 In some young specimens the prevailing shade is yellowish-green, in place 

 of the red. In others again, the radioles are of a uniform brick-red color 

 towards the base of the spine, and are only banded near the tip. Others are 

 of a uniform dull brick-red, with serrations of darker color, while still others, 

 usually those round the abactinal system, are of a uniform dark-violet 

 color. Seen from the lower side the primaries, as well as the secondaries 

 are of a uniform, dull, light-yellowish red, the latter being somewhat darker. 

 The larger and longer serrations on the edge of the primary radioles 

 are usually white ; the serrations of the upper side are usually of a brick- 

 red color, somewhat darker than the color of the transverse bands. In the 

 smaller specimens the banding of the radioles towards the tip is very 

 marked. 



The interambulacral secondary spines are long, slender, flattened, 

 and sharply pointed (Pis. 24, 25), of a dirty, greenish-brown color. The 

 ambulacral are more slender and pointed than the interambulacral seconda- 

 ries, but are of the same greenish-brown color as the median intermbulacral 



