CyENOPEDINA HAWAIIEXSIS. 219 



The primary tubercles are very large, especially at the ambitus. In the 

 interambulacra, their areolae coalesce vertically for nearly their full width, but 

 the uppermost and lowest are naturally not so extensively developed. In the 

 ambulacra, the areolae do not coalesce even at the ambitus but are separated by 

 a few minute miliaries. In both areas, the boss is moderately high without a 

 trace of crenulation, while the mamelon is very well formed and conspicuously 

 perforated. The larger secondary tubercles are also perforated and are other- 

 wise similar. The primary spines at and above the ambitus are long and slender, 

 those of the interambulacra greatly exceeding those of the ambulacra. They 

 are very finely striated longitudinally and very minutely rough. They are solid 

 but the central core is obviously less solid than the surrounding wall and towards 

 the tip of the spine becomes very poorly developed. Some of the smallest 

 primaries are perfectly hollow and the larger secondaries resemble them in that 

 respect as well as in general appearance. 



The pedicellariae are abundant but are mostly tridentate. The glohiferous 

 pedicellaria? (PI. 91, fig. 10) are nearly or quite confined to the abactinal system 

 and may be wanting even there. They are quite small but are easily detected 

 because of the brown or purple glands which enclose the valves. The latter are 

 about half a millimeter long and terminate in two very short, sharp, diverging 

 teeth (PI. 91, figs. 11, 12). The tridentate pedicellariae occur in a great variety 

 of sizes and forms and are found on all parts of the corona, as well as on the 

 abactinal system and occasionally even on the actinostome. They may have, 

 a short neck or none and the stalk may equal, or exceed more or less markedly, 

 the head. The valves may be straight and in contact for nearly their entire 

 length (PI. 91, fig. 4) or in contact only, to a varying amount, near the tip (PI. 91, 

 figs. 5, 6), or they may be strongly curved and in contact only at tip (PI. 91, 

 figs. 1,2). The length of the valves ranges from .35 to nearl}- 4 mm. The 

 thickness of the head at the base varies from one quarter to one half the length 

 (compare PI. 91, figs. 1 and 4 or J and 6). The ophiccphalous pedicellariae are 

 common but resemble some forms of the tridentate and are chiefly distinguished 

 by the loop on the valves. The latter (PI. 91, fig. 7) are somewhat elongated 

 with rather flattened blades and measure about .40-. 50 mm. No pedicellariae 

 of the form characteristic of the genus (PI. 91, figs. 14, 20) were found. The 

 triphyllous pedicellariae are not uncommon but are so small as to be easily o\er- 

 looked. The valves, which are about .20 mm. in length, show considerable 

 diversity in form, as the blade may be nearly circular, or narrow anil truncate 

 or, as is usually the case, broad and truncate; the one figured (PI. 91, fig. S) is 



