A MONOGRAPH OF THE EXISTING CRINOIDS 291 



exteriorly, nearly three times as broad as the interior length. The next four brachials 

 are oblong, nearly four times as broad as long, those following becoming almost tri- 

 angular, about three times as broad as long, then gradually lengthening (though 

 remaining almost triangular) to about twice as broad as long, and at a point some- 

 what beyond the proximal third of the arm rather quickly becoming wedge-shaped, 

 almost oblong, about two and one-half times as broad as long. From about the 

 ninth onward the brachials have prominent distal ends, though these do not overlap 

 the bases of the succeeding segments. 



Syzygies occur between brachials 3+4, 9+ 10, and 15+10 (the second sometimes 

 omitted), and distally at intervals of 7-10 muscular articulations. 



P D is 4.5 mm. long, moderately stout basally but tapering rapidly in the proximal 

 half and becoming slender distally , composed of 20 segments, which at first are about twice 

 as broad as long, becoming about as long as broad after the eighth ; the second-seventh 

 segments are rather strongly carinate. Pi is similar, very slightly longer and stouter. 

 P 2 is 6 mm. long, considerably stouter and stiff er than the preceding and rather more 

 strongly carinate basally, with about 20 segments of which the first 7 (except for the 

 carinate process) are squarish and the remainder slightly longer than broad, becoming 

 about half again as long as broad distally; the ridge in the distal half of the outer side 

 is but little marked. P 3 is 3 mm. long, much smaller than any of the preceding pin- 

 mules, composed of about 12 segments, which at first are broader than long, becoming 

 as long as broad at about the fifth and nearly twice as long as broad distally; the second- 

 fifth segments are carinate. The following pinnules are similar and of about the same 

 length, the segments becoming gradually longer and the basal carination gradually 

 less. The distal pinnules are 5 mm. long. On the arms arising from a IBr axillary 

 Pi, P 2 , and P 3 are usually as described for P D) P u and P 2 ; and P 4 is much smaller, as 

 described for P 3 ; but occasionally P 2 is enlarged and similar to P 3 as described, instead 

 of being small like P t . 



The disk bears a few calcareous granules in the anal area, especially on the anal 

 tube. 



Notes. — The specimens from Investigator station 549 have 15 and 27 arms. 



The specimen from Investigator station 548 has 20 arms. Of the nine IIBr series 

 present six are 4 (3 + 4) and three are 2. One IIIBr 2 series is present, developed 

 internally on a IIBr 2 series. The cirri are XV, with several additional rudimentary, 

 41-44, up to 35 mm. in length. 



One of the six specimens collected by the Patrol 80 miles northwest of Penang 

 may be thus described. The centrodorsal is discoidal, moderately thick, with the 

 bare dorsal pole flat, though with an irregular surface, 4 mm. in diameter. The cirrus 

 sockets are arranged in two alternating marginal rows. The cirri are XXII, 37-39, 

 about 35 mm. long. The first segment is short, and those following gradually in- 

 crease in length to the fifth or seventh, which is about as long as broad. In the longest 

 cirri the next 10 segments are subequal, somewhat longer than broad, and those 

 succeeding slowly decrease in length so that the distal are broader than long, though 

 never much so. On a segment somewhere between the fifteenth and the nineteenth 

 a subtcrminal dorsal tubercle appears, which, two segments beyond, becomes a con- 

 spicuous dorsal spine and, in lateral view, appears as a narrow triangle with the sharp 

 apex terminal, arising from the entire dorsal surface of the segment and in height 



