A MONOGRAPH OF THE EXISTING CRINOIDS 247 



to be parallel to the longitudinal axes of the segments. The opposing spine is small, 

 but prominent, and terminal in position. 



The ends of the basal rays are very prominent in the interradial angles of the calyx. 



The radials are concealed by the centrodorsal. The IBri are very short, crescentic, 

 the lateral edges thickened and more or less everted, and the proximal edge thickened 

 and more or less tubercular or crenulate; a rather high, strongly rounded, dorsoven- 

 trally elongate tubercle occupies the median dorsal line. The IBr 2 (axillaries) are tri- 

 angular, twice as broad as long, with a high median tubercle resembling that on the 

 IBr; the distal portion of which bends to one side or the other reaching almost or quite 

 to the base of the IIBri. Of the 10 IIBr series present 9 are 4(3+4) and one is 2. 

 They are strongly and evenly convex dorsally. The 2 distal elements are slightly 

 separated interradially by the carinate basal segments of P D . The ossicles of the IIBr 

 series bear rounded median tubercles similar to those on the IBr series, but somewhat 

 less high. The IIIBr series are 2(1+2), developed internally in 1, 2, 2, 1 order. Two 

 IVBr series are present, both 2(1+2), one internal in reference to the preceding IIIBr 

 series, the other internal in reference to the preceding IIBr series. The lower part of 

 the animal is broad and stout and broadly rounded so that the profile resembles in 

 general that of the larger species of Crinometra. 



The 33 arms are 130 mm. long. The proximal oblong brachials have a slight trace 

 of a low median tubercle, and the outer brachials overlap slightly. 



Notes. — Professor Gislen says that in the single specimen from Bock's station 36 

 the centrodorsal is rounded conical, the free dorsal pole without tubercles, 3 mm. 

 broad at the base and 1.5 mm. high. The cirrus sockets are arranged in a single or 

 double row, and in 10 columns. 



The cirri are XIX, 14-16, from 14-17 mm. long, and are very stout. The fifth 

 segment is the longest, half again as long as broad. From the eighth segment onward 

 there is a dorsal longitudinal crest. The ventral margin of the distal segments is about 

 as long as the width. The opposing spine is in height equal to one-third the width of 

 the segment. The terminal claw is curved and somewhat longer that the preceding 

 segment. 



The basals project as large interradial prominences. 



The radials are eight times as broad as long and bear a median tubercle. The 

 IBrj are five times as broad as long and are laterally united. The IBr 2 (axillaries) are 

 three times as broad as long. There is a median tubercle on the IBri and on the proxi- 

 mal portion of the IBr 2 , and similar tubercles on the ossicles of the IIBr series. The 

 IIBr series are 4(3+4). The IIIBr series are 2, developed internally. The elements 

 of the IIIBr series and the first two brachials have slight median tubercles. The first 

 segments following each axillary are united internally. 



The 18+ arms are 70 mm. long. The first 12 brachials are discoidal, those follow- 

 ing wedge-shaped. The distal brachials have a low dorsal spine which does not overlap 

 that on the brachial succeeding. The brachials are sharply flattened laterally as far 

 as the twelfth. The bases of the P D are visible between the arm bases. 



The first syzygy on the inner side is usually between brachials 1 + 2; the distal 

 intersyzygial interval is 4 oblique muscular articulations. 



P D is about 5 mm. long with 22 segments which are thickened and bear dorsal 

 prominences similar to those found in the family Calometridae. The first segment is 



