676 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



memoir convinced me that ingolfiana is not separable from americana or from aspera, 

 and that all these names fall in the synonymy of cubensis. 



In 1941, H. L. Clark recorded a fine specimen of cubensis from the Atlantis col- 

 lections off Cuba. 



The most recent record from the North Atlantic is that of Einarsson from south 

 of Iceland in 1948. 



TRICHOMETRA DELICATA A. H. Clark 



Anledon sarsii (part) WTVILLE THOMSON, Proc. Roy. Soc. Edinburgh, vol. 7, 1872, p. 764 (the south- 

 ern specimens); The depths of the sea, 1873, p. 124 (same). DE FOLIN, Sous les mers, 1887, p. 

 126 (near Santander, 960 and 1081 meters). 



Antedon dentata (part) P. H. CARPENTER, Proc. Roy. Soc. Edinburgh, vol. 12, 1884, p. 363 (Porcupine 

 station 17A, 1870). FILHOL, La vie au fond des mers, 1885, p. 213. 



Antedon tenella (part) P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 171 

 (Porcupine sta. 17A, 1870); Journ. Linn. Soc. (Zool.), vol. 24, 1891, p. 53. 



Trichomelra delicata A. H. CLARK, Bull. Mus. Hist. Nat., Paris, No. 4, 1911, p. 258 (description; 

 Travailleur sta. XIII, 2030 meters) ; Unstalked crinoids of the Siboga-Exped., 1918, p. 247 (in 

 key; range), p. 248 (references); The Danish Ingolf-Exped., vol. 4, No. 5, Crinoidea, 1923, p. 43 

 (range), p. 56 (in key), p. 58 (Ingolf sta. 18). ELIAS DA COSTA, Chaves dieotdmicas para a 

 classificacao dos equinodermes Portugueses. IV. Crin6ides, Porto, 1940, p. 13. LE DANOIS, 

 Les profundeurs de la mer, Paris, 1948, pp. 176, 245. (Not T. delicata A. H. Clark, 1913, nor 

 Mortensen and Koehler, 1927, which are all Orthrometra hibernica.) 



Diagnostic features. This species resembles T. cubensis in the number of the cirrus 

 segments, but the cirri are more slender and the segments do not become as long as 

 broad until about the twentieth. The elements of the IBr series and the earlier brach- 

 ials are strongly convex dorsally and just in lateral contact, but not laterally flattened. 

 Trichometra delicata appears to be a smaller species than T. cubensis. 



Description. The cirri are very numerous, composed of 27 to 33 segments, of 

 which the two first are very short, the third is slightly broader than long, and the fifth 

 is the longest, three times as long as the median width; the following segments gradu- 

 ally decrease in length, after about the twentieth becoming about as long as broad. 

 The longer proximal segments are very strongly constricted centrally, with the ends 

 much expanded, the distal ends overlapping the bases of the segments succeeding. The 

 short distal segments are strongly carinate dorsally. 



The distal borders of the radials just reach the edge of the centrodorsal ; their in- 

 terradial angles are moderately produced. The IBri are very short, four or five times 

 as broad as long, with then- lateral edges parallel. The IBr 2 are lozenge-shaped, half 

 again as broad as long, with the anterior angle very sharp. The ossicles of the IBr 

 series are strongly rounded dorsally and laterally and in intimate contact with their 

 neighbors on either side, though not laterally flattened. Their proximal and distal 

 edges are prominently spinous. 



The 10 arms are 37 mm. in length; they resemble those of T. vexator, but the brach- 

 ials are relatively slightly longer. The oblong brachials at the base of the arms have 

 their distal borders abruptly and strongly everted and fringed with long spines; the 

 triangular brachials have their distal borders moderately produced and overlapping the 

 bases of those succeeding. 



Syzygies occur between brachials 3+4, 9 + 10, 14+15, and distally at intervals of 

 2 (more rarely 3) muscular articulations. 



