488 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME l 



IIYPAl.OMETRA DEFECTA (P. H. Carpenter) 



FiGUBE 24 



[See also vol. 1, pt. 1, fig. 388 (p. 307); pt. 2, figs. 85-86 (p. 53), 297 (p. 53), 297 (p. 221), 768 (p. 362)| 



Antedon, sp. P. H. Carpenter, Bull. Mus. Comp. Zool., vol. 9, No 4, 1881, p. 155 (found with 

 Antedon [Coccomelra] hagenii; deficient pinnulation). 



Antedon defecta P. H. Carpenter, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 206 (in key), 

 p. 207 (taken by Blake), pp. 367, 368 (depths), p. 378 (Caribbean Islands; 77-242 fms.).— 

 MiNCKEHT, Arch. Naturg., Jahrg. 71, vol. 1, 1905, Heft 1, p. 171 (syzygies; pinnulation; regenera- 

 tion). — Hamann, Bronn's Klassen und Ordnungen des Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1580 

 (listed). — Hartlaub, Mem. Mus. Comp. Zool., vol. 27, No. 4, 1912, p. 280 (in Blake collection), 

 pp. 381-384 (?loc.; detailed description of two of Carpenter's specimens; discussion), p. 391 

 (identified with species with deficient pinnulation mentioned in Carpenter, 1881), pi. 6, figs. 1-4, 

 pi. 14, fig. 11. 



Ilypalometra defecta A. H. Clark, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 133 (listed); Un- 

 stalked Crinoids of the Siboga-Exped., 1918, p. 236 (references) ; The Danish Ingolf-Exped., vol. 4, 

 No. 5, Crinoidea, 1923, p. 42 (range).— Gisl£n, Zool. Bidrag Uppsala, vol. 9, 1924, pp. 42, 44, 

 53.— A. H. Clark, Mem. Soc. Cubana Hist. Nat., vol. 14, No. 2, 1940, p. 141 (in key), p. 159 

 (references); Bull. U.S. Fish. Comm., vol. 55, 1954, p. 374 (listed). 



Description. — The centrodorsal is small, subconical to hemispberical. The cirrus 

 sockets are numerous, usuallj' almost completely covering the centrodorsal though 

 there may be a more or less extensive bare polar area; they are arranged in closely 

 crowded row s which are more or less irregular, and about the rim of the centrodorsal 

 there are approximately 3 sockets beneath each radial. 



The cirri are XX-XXX, 22-25 (Hartlaub gives as a maximum about 30), 10 mm. 

 long. The first segment is short, the second is about as long as broad, the third and 

 fourth are the longest, about 3 times as long as broad, and those following gradually 

 decrease in length, the segments in the distal haK of the cirri being about as long as 

 broad. The second to fifth segments are constricted centrally with swollen ends; 

 those succeeding broaden gradually from their proximal to their distal ends, the latter 

 overlapping the bases of the following segments. The short segments in the distal 

 third of the cirri sometimes bear more or less well-developed dorsal spines, and some- 

 times show but shght traces of them. The opposing spine is very prominent, about 

 equal in height to the width of the penultimate segment, of which its base occupies 

 the distal half of the dorsal side; it is rather narrow and very sharp. The terminal 

 claw is rather longer than the penultimate segment, and is rather strongly cm'ved. 



The radials are short in the middorsal line but extend well up into the interradial 

 angles where their anterolateral corners are separated by a narrow cleft. The IBr, are 

 very short in the median line, but laterally almost as long as broad. The IBro (axil- 

 laries) arc almost square with the sides somewhat concave, and their proximal projec- 

 tion deeply incises the IBr,; their lateral angles extend beyond the anterolateral 

 comers of the IBrj. The IBr series are narrow and laterally well-separated. 



The 10 arms are from 25 to 35 mm. (most commonly between 25 and 30 mm.) 

 in length. The fij-st bracliials are short, about twice as long on the outer as on the 

 inner side, incised by the second bracliials, which are considerably larger and irregu- 

 larly quadrate. The first S3^zygial pair (composed of brachials 3-|-4) is about as 

 long as broad with the ends concave. The fifth to eighth brachials are very slightly 

 wedge-shaped, almost square, those following becoming very obliquely wedge-shaped, 

 longer than broad, and elongate and centrally constricted in the outer two-thirds of 



