488 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



HYPALOMETRA DEFECTA (P. H. Carpenter) 



FIGURE 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. CAKPENTEB, Bull. Mus. Comp. Zool., vol. 9, No. 4, 1881, p. 155 (found with 

 Antedon [Coccometra] 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.). 

 MINCKERT, 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). HARTLATJB, 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. 



Hypalometra 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). GISLEN, 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 hemispherical. The cirrus 

 sockets are numerous, usually almost completely covering the centrodorsal though 

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

 crowded rows 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 half 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 slight 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 curved. 



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 t are 

 very short in the median line, but laterally almost as long as broad. The IBr 2 (axil- 

 lanes) are almost square with the sides somewhat concave, and their proximal projec- 

 tion deeply incises the IBrij their lateral angles extend beyond the anterolateral 

 corners of the IBiv 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 first brachials are short, about twice as long on the outer as on the 

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

 larly quadrate. The first syzygial 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 



