A MONOGRAPH OF THE EXISTING CRINOIDS IQl 



longer than Pj. The lower pinnules are strongly prismatic. The sharp prismatic 

 ridge probably is what induced Carpenter to call them carinate. 



Decametra mylitta was described by me in 1912 from a specimen dredged by the 

 Siboga at station 99. It was redescribed and figured in my report on the unstalked 

 crinoids of the Siboga expedition published in 1918, when notes were given on another 

 specimen from the type locahty, and also on one from Albatross station 5139. 



In 1927 Dr. Torsten Gisl6n gave notes on a specimen in the Upsala Museum that 

 he referred to D. mylitta. He did not, however, mention the locality from which it 

 came. His mention of this specimen was incidental to his description of a specimen 

 of Oligometra japonica collected by Dr. Th. Alortensen which he said it resembled 

 rather closely, though the cirrus segments are somewhat shorter and the pro.ximal 

 pmnules are somewhat compressed and flagellate, and the outer segments are pro- 

 vided with spiny whorls at their distal ends. 



DECAMETRA MOLUS (A. H. Clark) 



Plate 24, Figure 122 

 [See also vol. 1, pt. 1, fig. 349 (cirrus), p. 291.) 



Cyllometra mollis A. H. Clark, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 76 (description; 

 Kurrachi). 



Decametra mollis A. H. Clark, Ann. Mag. Nat. Hist., ser. 8, vol. 10, 1912, p. 36 (compared with 

 D. mylilta); Crinoids of the Indian Ocean, 1912, p. 161 (synonymy; detailed description; local- 

 ity; notes), fig. 24, p. 162; Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 35 (Kurrachi; 

 description); Unstalked crinoids of the (Sibopo-Exped., 1918, p. 117 (in key; range), p. 120 

 (compared with D. mylitta); Journ. Linn. Soc. (Zool.), vol. 36, No. 249, May 1929, p. 643 

 (Muhlos, Maldives); John Murray Exped. 1933-34, Sci. Reports, vol. 4, No. 4, 1936, p. 101 

 (range), p. 103. — Mortensen, Danish Scientific Investigations in Iran, pt. 2, 1940, p. 59 (Per- 

 sian Gulf). — GiSLfiN, in Mortensen, Danish Scientific Investigations in Iran, pt. 2, 1940, p. 

 Ill (off Kharg Island; Stifi'e's Bank). 



Diagnostic features. — The cirri are 10 mm. long with 20-23 segments of which 

 the five or six preceding the penultimate are almost or quite as long as broad; Pj 

 is the largest and longest pinnule with 14-17 segments of which the distal are t\vice as 

 long as broad and the second and following have projecting outer corners or a few 

 spines on the distal edge; the arms are 65 mm. long. 



Description. — The centrodorsal is discoidal, thiu, with the bare polar area flat, 

 2 mm. in diameter. The cirrus sockets are arranged in one and a more or less partial 

 second crowded marginal rows. 



The cirri are XX, 20-22, 10 mm. long. The first segment is short, the second 

 and third are about twice as broad as long, and the remainder are very slightly broader 

 than long, becoming almost as long as broad in the terminal five or six. The second 

 and following segments have the distal dorsal edge produced and finely spinous, this 

 projection progressively narrowing dis tally, at the same time very slowly moving to a 

 more proximal position, after about the eighth becoming a pair of small subterminal 

 tubercles which on the last five to seven segments give place to small median tubercles. 

 The opposing spine is much larger than the spines on the preceding segments, in 

 lateral view triangular with the apex terminal to almost median, in height reaching to 

 one half or rather more of the width of the penultimate segment. The terminal claw 



