170 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



species of Thalassometra, and the synonymy and range were given. In 1929 I recorded 

 a small specimen that had been found on a cable brought to the surface from an unre- 

 corded depth by the cable repair ship Patrol, of the Eastern and Associated Telegraph Co. 



THALASSOMETRA HAWAIIENSIS (A. H. Clark) 



[See vol. 1, pt. 1, figs. 195, 196, p. 237; pt. 2, fig. 223, p. 175.] 



Antedon hawaiiensis A, H. CLARK, Proc. U. S. Nat. Mus., vol. 33, 1907, p. 152 (description; Albatross 



station 3475). 

 Thalassometra hawaiiensis A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 360 (listed); 



Proc. TJ. S. Nat. Mus., vol. 34, 1908, p. 222 (Albatross stations 3475, 3476); Proc. Biol. Soc. 



Washington, vol. 22, 1909, p. 14 (listed); Crinoids of the Indian Ocean, 1912, p. 203 (locality); 



Die Crinoiden der Antarktis, 1915, p. 124 (shows characteristic features of Anthometra adriani) ; 



Unstalked crinoids of the Si&oja-Exped., 1918, p. 168 (in key; range), p. 170 (references) ; Bernice 



P. Bishop Mus. Bull. 195, 1949, p. 74 (Albatross stations 3475, 3476), p. 87 (station data). 



Diagnostic features. The elements of the division series and first two brachials are 

 bordered with thickly set spines; the triangular proximal brachials have projecting 

 distal edges which increase hi prominence distally, in the distal third of the arms 

 becoming long curved overlapping spines; and the cirri are arranged in 10 definite 

 columns on the centrodorsal. The 10-12 (usually 10) arms are 110 mm. long, and the 

 cirri are 32 mm. long with 50-55 segments. 



Description. The centrodorsal is large, hemispherical or short columnar. The 

 cirrus sockets are arranged in 10 columns of 1 or 2 each, and the columns are segregated 

 into 5 radial pairs, each pair being separated from its neighbors on either side by a 

 shallow groove, which is about as broad as the transverse diameter of a cirrus socket. 



The cirri are XX, 50-55, 32 mm. in length. The first 3 segments are short, the 

 fourth is about as long as broad, and those following increase in length to the seventh, 

 which is the longest, about twice as long as broad. The succeeding segments decrease in 

 length, becoming broader than long after the thirteenth and very short distally. Cari- 

 nate dorsal spines begin to appear at about the tenth segment, and become very prom- 

 inent distally. The first six segments and the proximal three-quarters of the seventh 

 are dull yellowish, with a dull surface ; the distal quarter of the seventh and the succeed- 

 ing segments are white and highly polished. In lateral view the cirri taper gradually 

 from the base to the middle of the seventh segment, remaining uniform in width from 

 that point onward. 



The disk, brachial and pinnule ambulacra are bordered with remarkably well 

 developed plates. Sacculi are fairly well developed. 



The ends of the basal rays are visible as small tubercles in the interradial angles of 

 the calyx. 



The radials are just visible beyond the rim of the centrodorsal, appearing crescentic 

 hi shape. The IBri are more than twice as broad as long, with the distal border incised 

 by the rounded proximal extension of the axillary. The IBr 2 (axillaries) are rhombic 

 about half again as broad as long. The junction between the two elements of the IBr 

 series rises into a slight tubercle. The IIBr series, when present, are 4(3+4). The 

 IBri, IIBrj and first two brachials are bordered all around with thickly set spines. The 

 division series and proximal brachials are in close lateral apposition and are sharply 

 flattened laterally. 



