232 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



In my memoir on the unstalked crinoids of the Siboga expedition published in 

 1918, I recorded this species from stations 164 and 258 and gave notes on the 

 specimens. 



In 1921 in his memoir on the echinoderms of Torres Strait Dr. Hubert Lyman 

 Clark under the heading Oligometra carpenteri said that Merton took five specimens 

 in June 1908 on the northern coast of Little Kei Island. These five specimens are 

 the ones that were correctly identified as 0. serripinna and described by Reichen- 

 sperger in 1913. 



In 1929 I recorded and gave notes on two specimens that had been collected at 

 Muhlos, Maldive Islands, by Prof. J. Stanley Gardiner, and in 1932 I recorded and 

 gave notes on a specimen from Madras that had been collected in 1918 by Dr. Stanley 

 Wells Kemp. 



OLIGOMETRA SERRIPINNA var. MACROBRACHIUS A. H. Clark 



PLATE 27, FIGURES 141, 142 



Oligometra serripinna (part) REICHENSPERGEK, Abh. Senck. Naturf. Ges., vol. 35, No. 1, 1913, p. 83 



(Kei Islands), p. 105 (notes). 

 Oligomelra serripinna var. macrobrachius A. H. CLARK, Temminckia, vol. 1, 1936, p. 310 (characters; 



Ternate, 2-4 meters), pi. 9, figs. 10, 11. 



Diagnostic features. The arms are very long, up to 110 mm. in length; P ft is 

 usually absent; and the outer cirrus segments usually bear paired dorsal tubercles 

 instead of a transverse ridge. 



Description. The centrodorsal is a thin circular disk with the dorsal pole flat, 

 2.5 mm. in diameter. The cirrus sockets are arranged in a single regular marginal row. 



The cirri are XV, 21-22 (usually 21), about 12 mm. long. The first segment is 

 very short and those following gradually increase in length so that the two or three 

 before the penultimate are only slightly broader than long. Most of the segments are 

 about half again as broad as long. On the fourth segment the distal dorsal edge 

 becomes prominent. On the segments succeeding this prominence slowly increases 

 in height, moves slightly anteriorly, and becomes narrower, forming a low submedian 

 transverse ridge; on the last five to seven segments before the antepenultimate this 

 transverse ridge is represented by paired conical tubercles, and on the antepenultimate 

 by a single median pointed tubercle. The opposing spine is prominent, conical, 

 and erect, in height equal to about half the width of the penultimate segment. The 

 terminal claw is longer than the penultimate segment and is strongly curved in the 

 basal third, but becomes nearly straight distally. 



The radials are low, 6-8 tunes as broad as long, and are separated interradially 

 by a narrow notch. The IBri are oblong, three times as broad as long, with the 

 lateral edges straight and parallel. The IBr 2 (axillaries) are broadly pentagonal, twice 

 as broad as long, with the parallel lateral edges about two-thirds as long as those of 

 the IBi-]. The IBr series have a synarthrial tubercle which is very narrow and is 

 continued basally to the proximal border of the IB^ in the form of a low rounded cari- 

 nation. 



The 10 arms are 110 mm. in length, long, slowly tapering, and very slender. The 

 first brachials are wedge-shaped, half again as long exteriorly as interiorly, ulteriorly 

 united in the proximal two-thirds, the sides diverging at almost a right angle beyond 

 the point of union. The second brachials are larger than the first, wedge-shaped, twice 



