ECHINOSTREPHUS ACICULATUS. 343 



Neither the pedicellarise, sphseridia, or spicules show any constant differences 

 between the two species but there is more or less individual diversity. The 

 globiferous pedicellarise are large and conspicuous (PI. 95, fig. 23) and it is inter- 

 esting to find that while the valves usually have a lateral tooth on only one side, 

 occasionally they occur with such a tooth on each side (PI. 95, fig. 2Ji). This 

 emphasizes the intermediate position occupied by the genus. The tridentate 

 pedicellariae are not usually common and they show the greatest diversity in 

 size, and nearly as much in form; the valves measure from .20 mm. to over a 

 millimeter in length. Most of our Hawaiian specimens lack tridentate pedjcel- 

 lariae, although globiferous and ophicephalous are common. When tridentate 

 are common, they are chiefly actinal in position, and ophicephalous are rare. 

 The ophicephalous on the buccal plates are much smaller than those on the test. 

 The latter have the valves about half a millimeter long, including the loop; 

 they are provided with long muscular necks ; the valves are constricted near the 

 base of the very coarsely serrate or sinuate blade. The triphyllous pedicellarise 

 have valves .15-.20 mm. long and .10-. 15 mm. across the blade. Spha}ridia 

 are numerous, 15-20 on the actinal part of each ambulacrum, but not extending 

 to the ambitus. 



The "Albatross" specimens show great diversity in size and color. The 

 largest (PL 105, fig. 9) is 37 mm. in diameter and nearly 25 mm. high; the 

 ambitus is about 6 mm. above the equator. The longest primaries, which are 

 very near the abactinal system, are 30 mm. in length. The test is dull grayish 

 or purplish with a slight greenish tinge on the primary tubercles. The primary 

 spines are very dark, almost bronze color and those below the ambitus are 

 abruptly tipped with deep pink. This specimen is from Laysan Island. Another 

 from the same vicinity differs strikingly in color, but is not otherwise peculiar. 

 The test is dull lavender with no trace of green; the secondaries, and the basal 

 half of the primaries below the ambitus, are bronze-brown; the abactinal pri- 

 maries and the terminal half of the actinal, are very pale lavender, almost white, 

 with more or less of a pink shade, especially at the very tip. The smallest of 

 the Hawaiian specimens is 12 mm. in diameter. It is of interest because, as 

 might be expected, there are only three pore-pairs in an arc actinally, but from 

 the ambitus, which nearly coincides with the equator, upward, each arc has four. 



It is a noteworthy fact, that all of the "Albatross" specimens are from the 

 extreme northwestern part of the Hawaiian group, as will be seen from the fol- 

 lowing list of the stations where Echinostrephus was taken. 



Station 3959. Off Laysan Island, Hawaiian Islands. Bott. temp. To** ? 

 10 fathoms. Wh. s., co. 



