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 a . 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 10-11 

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

 the arms mostly apparently about 50 mm. long. 

 d'. 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. Carpenter, 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, 

 Crinoidsof the Indian Ocean, 1912, p. 33 (identity). — Koehler, Echinodermes des mers d'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 in 10 definite columns on the centro- 

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

 30-35 segments. 



