.} J BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Description. — The centrodorsal is thick discoidal, about 4 mm. in diameter at the 

 base and 1.5 mm. high, with the broad rugose dorsal pole about 3 mm. in diameter. 

 The cirrus sockets arc arranged in 15 crowded columns of one or two each, there being 

 three columns in each radial area; but rarely the median column is absent, leaving two 

 lateral columns separated by a bare slightly depressed space as broad as a column, 

 or the central column may consist of a single more or less undeveloped cirrus. The 

 radial areas on the centrodorsal are not usually differentiated, but in rare cases there 

 is a narrow sharp ridge that runs down from the ends of the basal rays. 



The cirri arc XXV, 31-40 (apparently usually about 35), up to 33 mm. in 

 length. The first segment is three or four times as broad as long or even shorter, the 

 second is about twice as broad as the greatest (ventral) length, the third is about half 

 again as broad as long, the fourth varies from slightly broader than long to about one- 

 third again as long as broad, and those following increase in length to the eighth, a transi- 

 tion segment , which is three times as long as the median width. The succeeding segments 

 rapidly decrease in length, the eleventh or twelfth being about as long as broad and 

 the seventeenth and following about half again as broad as long, or sometimes slightly 

 longer. The central portion of the distal dorsal edge of the transition (eighth) segment 

 is slightly produced; on the segments following this is raised into an abrupt high process 

 arising from the end of the second third of the dorsal surface of the segment with, 

 when viewed along the axis of the cirrus, a rounded or more or less lobate distal end. 

 Distally this process gradually narrows and at the same time arises from more and more 

 of the dorsal surface of the segments, becoming on the short outer segments a high and 

 conspicuous dorsal spine with a strongly rounded, but not carinate, dorsal crest, and 

 a roundedly blunted tip. The opposing spine is small, smaller than the dorsal spine 

 on the preceding segment, and blunt; it is terminally situated. The terminal claw is 

 longer than the penultimate segment, rather slender, and moderately and evenly 

 curved. 



The ends of the basal rays are prominent in the angles of the ctdyx as rather small 

 tubercles between the apposed anterolateral angles of the radials and the rim of the 

 centrodorsal. 



The radials are short, strongly curved, with the dorsal surface depressed within the 

 rim of the centrodorsal, especially laterally, making the ends of the basal rays conspic- 

 uous. The IBri are very short, about six times as broad as the median length, and 

 are in lateral contact. The midradial line bears a rather high median carination. 

 The anterolateral angles may bear single tubercles or short blunt spines. The !Br 2 

 (axillarics) are very short, about three times as broad as long, and are rhombic with 

 the lateral angles slightly truncated. The entire median line is occupied by a rather 

 high narrow (urination, and the edges are slightly everted and produced, most so on the 

 proximal .side. Prominent water pores are present beneath the apposed lateral angles 

 of the axillaries. The IIBr series are 2, resembling the IBr series; but the component 

 elements arc proportionately longer and the axillaries have much more broadly trun- 

 cated lateral angles. Rather conspicuous water pores are present on both sides of the 

 LBr series. The IIIBr series are 2, always externally developed, and resemble the 

 II Br series. The outer side of the IIIBr axillaries is about three times as long as the 

 inner, the latter being broadly cut away for the formation of the water pore. 



