A MONOGRAPH OF THE EXISTING CRINOIDS 37 



The radials are almost entirely concealed by the centrodorsal. They are very 

 short in the median line, but are somewhat longer laterally, the distal border being 

 gently concave. The IBri are short, about four times as broad as the median length, 

 with the proximal and distal borders nearly straight and parallel and the sides con- 

 verging slightly distaUy. They bear conspicuous ventrolateral processes which are 

 broadest at the distal angle. The IBrj (a.xillaries) are broadly pentagonal, and are 

 nearly twice as broad as long. Their sides are about as long as the sides of the IBrj 

 and, as they converge slightly pro.ximally, they make with these a very broadly obtuse 

 angle. They bear on either side a conspicuous ventrolateral process which is as high 

 as the maximum (distal) height of that on the IBri. The proximal and two distal 

 sides are nearly straight. The IIBr series resemble the IBr series, but the ventro- 

 lateral processes on the outer sides of both elements extend for their entire length, 

 and these processes are lacking on the inner sides. The IBrj are interiorly in contact 

 for the proximal two-thirds, diverging distally at somewhat more than a right angle. 

 The IIIBr series resemble the IIBr series, but the distal portion of the adjacent bor- 

 ders of the IlIBri diverge at a right angle or less, and the ventrolateral processes are 

 narrower and more ventral in position. The division series and first four brachials 

 have an obscure broadly rounded median carination. 



The 38 arms are 105 mm. long. The first brachials are shghtly wedge-shaped, 

 about two-thirds as long interiorly as exteriorly and about twice as broad as the median 

 length. They are interiorly united for the proximal three-fourths beyond which 

 point their interior borders diverge at a right angle. They bear exteriorly a ventro- 

 lateral process with a straight edge which is as broad as that on the preceding a.xillary. 

 The second brachials are of about the same size as the fust or slightly smaller, and 

 are also slightly wedge-shaped. Owing to the presence of Pj they lack the ventrolateral 

 process. The first syzygial pair (composed of brachials 3+4) is oblong, and is nearlj^ 

 as long as broad. The next four brachials are oblong, about three times as broad as 

 long. The brachials succeeding rapidly become triangular, twice as broad as long, 

 after the proximal fourth of the arm obliquely wedge-shaped, twice as broad as long, 

 and distally less obliquely wedge-shaped and longer. On the sixteenth or seventeenth 

 brachial the median portion of the distal border is fringed with fine spines. On 

 the brachials following this spinous fruige rapidly broadens and becomes more promi- 

 nent, though the spines scarcely increase in length. Beyond the middle of the arm 

 the dorsal surface of the brachials slowly becomes roughened, and finally more or less 

 spinous. On the proximal oblong brachials the dorsal surface is more strongly 

 curved centrally than laterally, so that the arms show a very obscure broadly romided 

 median ridge, but this gradually disappears as the brachials become wedge-shaped. 



Pi is 10-11 mm. long with 27-29 segments, tapering evenly and regularly and 

 becoming slender, delicate, and flagellate in the distal half. The first two segments 

 are about twice as broad as long, the fifth is about as long as broad, and the distal are 

 from half again to twice as long as broad. 



P2 is 10-11 mm. long with 2 1 or 22 segments, basally not quite twice as broad as Pi, 

 tapering very gradually, enlarged and stiffened, and moderately recurved toward the 

 arm tip. The first segment is about twice as broad as long, the second is of about the 

 same proportions or rather longer, the fourth is about as long as broad, and those 



