114 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Ocean published in 1912 Crotalometra eupedata and C. valida were listed, and the syn- 

 onymy and range of each were given. In a paper on the crinoids of the British Museum 

 published in 1913 notes were given on two specimens of Aglaometra lalida from Chal- 

 lenger station 214, and this form was compared with A. eupedata. In my memoir on the 

 unstalked crinoids of the Siboga expedition published in 1918 valida and eupedata were 

 included in a key to the species of Aglaometra, and the synonymy and range of each 

 was given. 



AGtAOMETRA INCERTA (P. H. Carpenter) 



[See vol. 1, pt. 2, pi. 14, fig. 1062, pi. 27, fig. 1166.] 



Antedon incerta P. H. CARPENTER, Challenger Reports, Zoology, vol. 11, part 32, 1884, pp. 57, 83 

 (occurrence of ambulacral grooves on the genital pinnules), pi. 54, figs. 6, 7; vol. 26, part 60, 

 1888, p. 106 (description; Challenger station 170A), pi. 18, fig. 4, 5. BATESON, Materials for the 

 study of variation, 1894, p. 421 (abnormal specimen). HARTLAUB, Bull. Mus. Comp. Zool., 

 vol. 27, No. 4, 1895, p. 131 (systematic and bathymetrical relationships). HUTTON, Index 

 faunae Novae Zealandiae, 1904, p. 290 (listed). HAMANN, Bronn's Klassen und Ordnungen des 

 Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1578 (listed). A. H. CLARK, Proc. Biol. Soc. Washington, 

 vol. 22, 1909, p. 18 (not placed in a revision of the Thalassometridae) ; Proc. U. S. Nat. Mus., 

 vol. 36, 1909, p. 404 (referred to Crotalometra) ; Crinoids of the Indian Ocean, 1912, p. 33 (of 

 P. H. Carpenter, 1888= Crotalometra incerta). 



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



Crotalometra incerta A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 33 ( = Antedon incerta P. H. 

 Carpenter, 1888), p. 209 (synonymy). 



Aglaometra incerta A. H. CLARK, Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 47 (published 

 references to specimens in the B. M.; Challenger station 170A; character of the IBr series); 

 Unstalked crinoids of the 5z6o</a-Exped., 1918, p. 163 (in key; range), p. 165 (references). 

 GISLEN, Ark. Zool., vol. 19, No. 32, Feb. 20, 1928, p. 7, No. 29 (Challenger station 170a; notes; 

 perhaps a Thalassometra). 



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

 close lateral contact; the proximal portion of the animal is broadly rounded, the pro- 

 files of the axillaries making with each other an angle of approximately 90, but the 

 arm bases being nearly parallel; and the cirri are long and stout, somewhat more than 

 half as long as the arms. The 10 arms are 90 mm. long, and the cirri are 50 mm. 

 long with 70 segments. 



Description. The centrodorsal is bluntly conical with the interradial angles at the 

 base slightly produced. The cirrus sockets are arranged in 10 columns, two to a 

 column, the two columns in each radial area being apparently either in apposition or 

 more or less separated in the midradial line. 



The cirri are about XX, nearly 70, sometimes reaching 50 mm. in length. The 

 ninth-twelfth segments are longer than broad, and those following gradually shorten 

 and develop a dorsal keel which is most marked in the middle third. 



The radials are barely visible. The elements of the IBr series are somewhat 

 sharply carinate. The IBr 2 (axillaries) and first brachials have sharp edges and 

 flattened sides. The second brachials and the hypozygals of the first syzygial pairs 

 are flattened on the inner side only. The articular line between the first two brachials 

 is somewhat tubercular. 



The 10 arms are probably about 90 mm. long and are composed of tolerably smooth 

 subtriangular brachials which gradually become quadrate. 



