PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 147 



Siboga station 167; Ceram Sea, off northwestern New Guinea (lat. 2°35.5' S., long. 

 131°26.2' E.); 95 meters; August 22, 1899 [A. H. Clark, 1912, 1918] (6, U.S.N.M., 

 E.449; Amsterdam M.). Type locality. 



Remarks. — Originally I considered the specimens from station 167 as representing 

 one species, which I called Compsometra longicirra, and those from station 50 as repre- 

 senting another, C. gracilipes. 



Compsometra longicirra I believed to differ from C. gracilipes in having longer cirri 

 (which does not appear to hold true) with more numerous segments (14-16 as against 

 12-13 in gracilipes), and Pi proportionately more slender with more elongated seg- 

 ments which are fewer in number (9 or 10 as contrasted with 11 in gracilipes) and pos- 

 sess only a slight eversion of their distal ends. 



But the largest specimens from station 167 have the arms from 30 to 40 mm. long, 

 while those from station 50 are smaller, the maximum arm length being only 23 mm , • 

 without doubt the difference in development accounts for the shght differences between 

 them. 



[Note by A.M.C] Following Gislen's synonymy of 1955, this species (longicirra) 

 is now referred to Antedon. 



ANTEDON PARVIFLOKA (A. H. Clark) 

 FlGUBE 9,6,c 

 Co ?«pso?«dra parw^ora A. H. Clark, Notes Leyden INIus., vol. 34, 1912, p. 13.3 (description; Siboga 

 Sta. 50); Unstalked crinoids of the Siboja-Exped., 1918, p. viij (discovery by the Siboga), p. 205 

 (in key; range), p. 207 (references; detailed description; Stas. 50, 65a, 99, 105, 125, 240, 289), 

 pp. 271, 272, 273, 274, 275 (listed), pi. 25, figs. 80, 81.— Gisl^n, Nova Acta Reg. Soc. Sci. Upsa- 

 liensis, ser. 4, vol. 5, No. 6, 1922, pp. 5, 124-126 (detailed notes; localities), pp. 182, 183 (listed); 

 figs. 109-113, p. 122; Zool. Bidrag Uppsala, vol. 9, 1924, p. 283.— A. H. Clark, Temminckia, vol. 

 1, 1936, p. 295, p. 316 (locality; notes); John Murray Exped. 1933-34, Sci. Reports, vol. 4, No. 

 4, 1937, pp. 102, 103. 



Diagnostic features. — A very small species with the arms up to only 35 mm. (but 

 rarelj' over 20 mm.) in length, and the cirri about a fifth as long; the cirri are less than 

 XL m the kno^\^l specimens, slender and delicate with 8 to 11 greatly elongated seg- 

 ments, of which the longest are about four tunes as long as their median widths, the 

 antepenultimate is about twice as long as broad, and the penultimate is from a third 

 to half again as long as broad and bears a prominent opposing spine ; all the cutus seg- 

 ments have greatly expanded distal ends, this feature becoming less marked distally; 

 P2 is about half as long as Pi; the centrodorsal L3 flattened hemispherical. 



Description. — Centrodorsal flattened hemispherical, very low, bearing two irregular 

 rows of cirrus sockets. 



Cirri XV-XXV, 8-9 (usually 8), 4 mm. long, exceedingly slender, the much elon- 

 gated segments with greatly expanded ends; first segment about twice as broad as long, 

 second from two to two and a half times as long as the diameter of the e.xpanded distal 

 end, third and fourth the longest, about three times as long as the diameter of the ex- 

 panded chstal ends or four times the median width; following segments decrease slowly 

 in length so that the antepenultimate is about twice as long as the diameter of its e.x- 

 panded distal end, and the penultimate is from a third to half again as long as broad; 

 the strong constriction of the middle of the segments decreases in amount distally; 

 opposing spine terminal, prominent, in height reaching nearly half the distal diameter 

 of the pemdtimate segment; terminal claw about as long as the penultimate segment, 

 rather stout, strongly and evenly curved. 



55G-G62— 67 11 



