A MONOGRAPH OF THE EXISTING CRINOIDS 577 



as long as broad, the second is slightly broader than long, the third is about one-third 

 again as long as broad, and the fifth and following are four or five times as long as 

 broad. The second and third segments, and the basal portion of the fourth, are cari- 

 nate. P 4 is 7.5 mm. long, with 15 segments. It is more slender than P 3 and tapers 

 more rapidly. The first two segments are slightly broader than long, the third is one- 

 third again as long as broad, the fifth is twice as long as broad, and those following 

 are three times as long as broad, becoming longer distally. The second and third 

 segments are carinate. P 5 is 4 mm. long, small, weak, and flexible, with 13 segments, 

 of which the first-third are carinate. The color is white proximally, shading into deep 

 purple beyond the proximal third of the arms. The division series and arms have a 

 narrow median deep purple line that coincides with the narrow carination. 



A much broken specimen with 2S arms from Siboga station 49a appears to belong 

 to this species. 



The specimen dredged by the Investigator off Great West Torres Island was 

 originally described as a new species under the name of Mariametra margaritifera. 

 The centrodorsal is rather small and discoidal. 



The cirri are XXI, 30-34, 15 mm. long. The outer segments bear long dorsal 

 spines. The radials are short, about six times as broad as long, and are gently convex 

 proximally and correspondingly concave distally. The IBr, are short, oblong, some- 

 what over four times as broad as long, and are in lateral apposition and slightly flat- 

 tened. The IBr 2 (axillaries) are short, almost or quite triangular, two and one-half 

 or three times as broad as long, and in lateral apposition. The radials and the portion 

 of the centrodorsal above the proximal row of cirrus sockets are evenly and thickly 

 covered with high small tubercles resembling those on the dorsal pole of the centro- 

 dorsal, this tubercular modification of the dorsal surface of the segments extending 

 distally in the interradial angles, occupying the lateral third of the IBr, and IBr 2 and 

 the IIBr series, thence diminishing in width and disappearing on the second brachial. 

 The inner borders of the IIBr series are similarly modified. The IBr series have a 

 low and narrow, but prominent, tubercular keel or row of tubercles. This is much 

 less marked, or altogether absent, on the IIBr series and first two brachials, though 

 it is sometimes traceable to the lowest of the triangular brachials. The elements of 

 the IBr and IIBr series and the proximal oblong brachials have prominently everted 

 dentate proximal and distal ends; as the brachials become wedge-shaped and trian- 

 gular the everted dentate ends become gradually lower, transforming into a rather 

 prominent finely spinous overlap that slowly dies away distally. The 18 arms are 

 apparently 30-35 mm. long. The proportions of the brachials are the same as in 

 M. subcarinata. 



Pi is 4 mm. long, moderately stout basally but tapering rather rapidly in the 

 proximal half and becoming slender distally, with 12 segments, of which the first 

 three are about as long as broad and those following increase in length and become 

 three or four times as long as broad distally. P 2 is 6 mm. long, slender, but stouter 

 than P : and somewhat stiffened, with about 16 segments, which at first are about as 

 long as broad but become three or four times as long as broad distally. P 3 is similar 

 to P 2 and of about the same size. The pinnules immediately following are small and 

 weak, about 3 mm. long. The distal pinnules are delicate, and about 5 mm. long. 



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