154 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



c 1 . Spines on the elements of the division series and lower brachials confined almost entirely to 

 the proximal and distal edges; centrodorsal with two converging columns of cirrus sockets 

 on the outer sides of each radial area, with the central column represented by a single 

 socket; larger, the 10-12 arms about 175 mm. long and the cirri about 40 mm. long with 

 60+ segments (Galapagos Islands and off Panama; 598-1,429 meters) ..agassizii (p. 158) 

 c 2 . Dorsal surface of the division series and lower brachials studded with stout, well-spaced, 

 sharply conical spines, the edges of the ossicles everted and crenulate, dentate, or serrate, 

 but not conspicuously spiny; cirri in 15 crowded columns of 2 or 3 each; smaller, the 1011 

 arms 95 mm. long and the cirri 33 mm. long with 40-50 (usually about 50) segments (western 



Aleutian Islands; 1,912 meters) villosa (p. 162) 



b 2 . Cirri with less than 40 (seldom more than 35) segments; spines on the division series and arm 



bases very fine and, at least along the edges, crowded; IIBr series, when present, 4(3 + 4). 

 c 1 . Elements of the division series and arm bases thickly covered dorsally with excessively fine 

 spines which are often grouped on irregular pedicels suggesting paxillae; larger, the 11 

 arms 80 mm. long and the cirri 20-25 mm. long with 31-38 (usually about 35) segments 



(Nicobar Islands; 1,024 meters) peripolos (p. 178) 



c 2 . Elements of the division series with scattered fine spines, or with finely spinous edges ; smaller, 



the arms mostly apparently about 50 mm. long. 



d 1 . Scattered spines on the elements of the division series and arms bases; 25-35 cirrus segments 

 e 1 . Spines on the division series and arm bases numerous; 25-30 cirrus segments (Ascension 



Island; 768 meters) multispina (p. 180) 



e 2 . Spines on the division series and arm bases few; 35 cirrus segments. (Tristan da Cunha; 



1,005 meters) setosa (p. 182) 



d 1 . Elements of the division series and arm bases without spines except along the proximal 

 and distal edges; brachials with the distal border thickened, forming a transverse crest 

 that bears only a few very fine spines; 21 cirrus segments (Canary Islands; 1,330-1,340 

 meters) omissa (p. 184) 



THALASSOMETRA BISPINOSA (P. H. Carpenter) 



Antedon bispinosa P. H. CABPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 115 (de- 

 scription; Challenger station 147), pi. 20, figs. 3, 4. HARTLAUB, Bull. Mus. Comp. Zool., vol. 

 27, No. 4, 1895, pp. 130, 131 (systematic position; bathymetric relationships), p. 134 (compared 

 with A. agassizii). SHIPLEY, Antarctic Manual, 1901, Chapter 18, p. 269. HAMANN, Bronn's 

 Klassen und Ordnungen des Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1578 (listed). A. H. CLARK, 

 Crinoids of the Indian Ocean, 1912, p. 33 (identity). KOEHLER, Echinodermes des mersd' Europe, 

 vol. 1, 1924, p. 58 (depth). 



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

 Amer. Nat., vol. 42, No. 500, 1908, p. 542 (belongs to a group characteristic of the oceanic area) ; 

 Geogr. Journ., vol. 32, No. 6, 1908, p. 603 (same); Proc. Biol. Soc. Washington, vol. 22, 1909, 

 p. 14 (listed); Crinoids of the Indian Ocean, 1912, p. 208 (synonymy; locality); Smithsonian 

 Misc. Coll., vol. 61, No. 15, 1913, p. 47 (published references to the specimen in the B. M.; 

 Challenger station 147); Journ. Washington Acad. Sci., vol. 5, No. 3, 1915, p. 81 (Antarctic; 

 range); Die Crinoiden der Antarktis, 1915, p. 105 (collected by the Challenger), p. 107 (in key 

 to Antarctic crinoids), p. 112 (synonymy; habitat), p. 169 (deep water Antarctic species), p. 

 170 (range and relationships), p. 192 (further discussion); Unstalked crinoids of the Siboga- 

 Exped., 1918, p. 166 (in key; range), p. 170 (references). GISLEN, Ark. Zool., vol. 19, No. 32, 

 Feb. 20, 1928, p. 7, No. 27 (notes). 



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

 bordered with numerous coarse blunt spines, and the eighth and following brachials 

 each have 2 or 3 long, curved, overlapping spines near the distal edge; the lower pin- 

 nules are very spiny; and the cirri are arranged hi 10 definite columns on the centro- 

 dorsal. The 10 arms are about 50 mm. long and the cirri are about 17 mm. long with 

 30-35 segments. 



