^57 



6. Thaumatometra thysbe A. H. Clark. 



A. H. Clark. Xotes from the Leyden Museum, vol. 34, 191 2, p. 149 {Thaumatometra thysbe). 

 Stat. 52. 9°3'.4.S., H9°56'.7E. Savu Sea. 959 Metres. 1 Ex. 



The centrodorsal is small, rounded conical. 



The cirri are about XL, 15 — 16, 9 mm. long; the lïrst segment is short, the second 

 about as long as the diameter of the expanded distal end, the third tvvice as long as the 

 diameter of the expanded distal end, and the fourth slightly longer; the following very slowly 

 decrease in length so that the last two before the penultimate are from one third to one half 

 again as long as broad; the earlier segments have greatly enlarged ends, the distal end being 

 much expanded and overlapping the base of the succeeding segment; as the segments become 

 shorter the dorsal and ventral profiles become straighter and the segments become compressed 

 laterally so that they appear broader in lateral view ; on the distal short segments the median 

 portion of the distal edge on the dorsal side projects slightly over the base of the following segment. 



In the median line the radials are just visible beyond the edge of the centrodorsal, but 

 they extend well up in the angles of the calyx; their distal angles are slightly separated so 

 that the bases of the IBi^ are not quite in apposition. 



The IBi'j are very short, almost oblong, about four times as broacl as the exterior 

 length, which is slightly greater than the median length; the lateral borders of adjacent IBrj 

 make an angle of about 90 with each other; the distal edges are narrowly everted and very 

 finely spinous. 



The IBr t (axillaries) are about as broad as long; the distal edges make approximately 

 a right angle with each other ; the distal angle is not produced ; a broad posterior process 

 incises the IBr, ; the lateral angles extend considerably beyond the distal angles of the IBi'j ; 

 the distal edges are evenly and very finely spinous. 



The arms are 30 mm. long and resemble those of the other species of the genus; the 

 distal edges of the brachials are moderately everted and finely spinous. Syzygies occur between 

 the third and fourth brachials, again between the ninth and tenth and fourteenth and fifteenth, 

 and distally at intervals of two oblique muscular articulations. 



Pj is excessively delicate, about 6. 5 mm. long, composed of 1 5 + segments of which 

 the first is very short, the second longer, the third about as long as broad, the fourth half 

 again as long as broad, the following becoming exceedingly elongated with swollen, produced 

 and overlapping spinous distal ends. P., is stouter than P n composed of 1 1 or 12 segments 

 of which those beyond the third are excessively elongated, becoming exceedingly slender distally; 

 the fourth-seventh segments bear a lartje denhal w-land. 



7. Thaumatometra brevicirra (A. H. Clark). 



A. H. Clark. Proc. U. S. National Museum, vol. 34, 1908, p. 235 {Bathymetra brevicirra). 



8. Thaumatometra parva A. H. Clark. 



A. H. Clark. Proc. U.S. National Museum, vol. 34, 190S, p. 231 {Thaumatometra parva). 



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