A MONOGRAPH OF THE EXISTING CRINOIDS 365 



in height, becoming very prominent on the short terminal segments though qever 

 exceeding more than one quarter of their width in height. The opposing spine and 

 terminal claw are as in A^. multicolor. 



The ends of the basal rays are visible as small tubercles or small rhombic 

 areas in the interradiul angles, but as they are not raised above the general surface 

 of the radials they are not especially obvious. 



The radials are short in the median line but extend upward in the interradial 

 angles in the form of an equilateral triangle the rounded apex of which entirely sepa- 

 rates the bases of the IBri. The IBrj are slightly trapezoidal, about two and one- 

 half times as broad as long, with the ventrolateral margins very thin. The IBrj 

 (axillaries) are pentagonal, as long as, or only very slightly shorter than, broad, with 

 the lateral edges nearly or quite as long as those of the IBrj, slightly constricted just 

 below the lateral angles. The IIBr series are 2, the IIBrj united in the proximal 

 two thirds, diverging at approximately a right angle distally. 



The 19 arms are 130 mm. long, resembling in the main those of N. multicolor. 

 The first brachials are wedge-shaped, about as long exteriorly as broad distally, 

 interiorly united for almost their entire length. The second brachials are similar 

 but swollen exteriorly to form an attachment for the greatly enlarged lower segments 

 of Pj. The first syzygial pair (composed of brachials 3+4) is from slightly longer 

 than broad to half again as long as broad and is slightly constricted centrally. The 

 next three or four brachials are wedge-shaped, progressively more and more oblique, 

 somewhat longer than broad, those following becoming triangular, as long as broad 

 with the exterior side somewhat convex, and wedge-shaped terminally. At about 

 the seventh brachial the distal edge becomes projecting and overlapping and armed 

 with fine spines, this projection on the side toward the longer lateral edge of the 

 brachials ending abruptly in a more or less pronounced sharp point or spine so that 

 the arms appear to have dorsally a double row of more or less marked short over- 

 lapping spines. Distally these spines gradually move nearer and nearer the median 

 line, at the same time becoming rounded carinate, finally dying away distally. 



Syzygies occur between brachials 3+4, again from between brachials 10+11, 

 to between brachials 12+13, and distally- at intervals of 3 (more rarely 2 or 4) muscular 

 articulations. 



Pi is 10 mm. long, very slender and weak, composed of 35 segments of whicli the 

 first is proportionately greatly enlarged, twice as broad as long, with a strong cari- 

 nate process, the second is much shorter, strongly trapezoidal, and the remainder 

 are very small and about as long as broad. Pj is somewhat longer, but stiff and spine- 

 like with elongated segments like P3. P3 is 20 mm. long, not especially stout but 

 verj^ stiff, with about 20 segments of which the first is about twice as broad as long, 

 slightly carinate, the second is trapezoidal, about as broad distally as the proximal 

 length, the third is half again as long as broad, the fourth is over twice as long as 

 broad, and the remainder are from two and one-half to tliree times as long as broad 

 and even longer distall}'. The segments have slightly projecting and spinous distal 

 ends, this feature increasing in intensity distally. P4 is similar to P3 and of the same 

 length. The pinnules following decrease to 12 mm. on Pj, then become somewhat 

 stouter, and more slender again distally, though remaining of the same length. The 

 segments in the distal portion of all the pinnules have prominent, somewhat expanded, 



