PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 805 



Eudiocrinus, sp. WOOD-MASON and ALCOCK, Ann. Mag. Nat. Hist., ser. 6, vol. 8, No. 48, December 

 1891, p. 443 (muddy bottoms in the Andaman Sea; 922 fms.). A. H. CLARK, Crinoids of the 

 Indian Ocean, 1912, p. 285 (previous reference is to Pentametrocrinus, sp.). 



Pentamelrocrinus varians A. H. CLARK, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 135 (listed); 

 Proc. U.S. Nat. Mus., vol. 34, 1908, p. 277 (listed), p. 319 (Japan); vol. 35, 1908, p. 117 (arm 

 structure); Smithsonian Misc. Coll., vol. 52, pt. 2, 1908, p. 234 (compared with P. diomedeae); 

 Rec. Indian Mus., vol. 7, pt. 3, No. 26, 1912, p. 271 (Investigator sta. 114) ; Crinoids of the Indian 

 Ocean, 1912, p. 33 ( = Eudiocrinus varians, P. H. Carpenter), p. 251 (synonymy; Investigator stas. 

 315, 331; descriptions and comparisons; other records); Smithsonian Misc. Coll., vol. 61, No. 15, 

 1913, p. 67 (published references to specimens in the B.M.; Challenger sta. 205); Journ. Wash- 

 ington Acad. Sci., vol. 5, 1915, No. 6, p. 215 (range and its significance); Unstalked crinoidsof 

 the Siboga-Exped., 1918, p. 260 (in key; range), p. 262 (references; notes; stas. 45, 48, 314), 

 pp. 271, 276 (listed); Smithsonian Misc. Coll., vol. 72, No. 7, 1921, pi. 2, fig. 24 (ambulacral 

 deposits), pi. 3, fig. 35 (proportions of the cirri). H. L. CLARK, Ann. South African Mus., vol. 

 13, 1923, p. 227, p. 229 (in key), p. 235 (station; range) [? this species]. GISLN, Zool. Bidrag 

 Uppsala, vol. 9, 1924, p. 26 (pinnulation) ; Ark. Zool., vol. 19, No. 32, 1928, p. 12 (notes); Lunds 

 Univ. Irsskr., new ser., vol. 30, No. 11, 1934, p. 17. A. H. CLARK, John Murray Exped. 1933-34, 

 Sci. Reports, vol. 4, No. 4, 1937, p. 87 (listed), p. 97 (station; notes; range), pp. 102, 104, 105. 

 GISLN, Kungl. Svenska Vet.-Akad. Hand!., ser. 3, vol. 17, No. 2, 1938, p. 4; Lunds Univ. Arsskr., 

 new ser., Avd. 2, vol. 34, No. 17, 1939, p. 16. 



Diagnostic features. The lowest pinnule is on the second brachial. In general 

 appearance this species closely resembles japonicus, from which it is readily distinguished 

 by the occurrence of a pinnule on the second brachial as well as by its somewhat more 

 slender build. 



Description. The centrodorsal is low hemispherical, with a large bare polar area 

 which usually shows marginal pittings representing obsolete cirrus sockets. The cirrus 

 sockets are arranged roughly in two rows; about the periphery of the centrodorsal 

 there are three beneath each radial. 



The cirri are XV-XXX (usually about XX), from 30 to 50 mm. long, composed of 

 18 to 22 (usually 20 to 22) segments. The first two segments are about twice as broad 

 as long, the third is about twice as long as its proximal width, or rather longer, and is 

 centrally constricted, the fourth is between three and four times as long as broad 

 (commonly about 2 mm. long), and the fifth is proportionately and absolutely longer 

 (up to 3 mm. in the largest examples). The following segments as far as the tenth are 

 similar to the fifth, those succeeding gradually becoming shorter. The terminal 7 or 

 8 segments form a tapering point to the cirri, the last two being very slender; these 

 segments thus become proportionately, though not absolutely, longer. The terminal 

 claw is straight and tapers to a sharp point; it is not quite so long as the penultimate 

 segment which, owing to its slenderness, is six or eight times as long as broad. The 

 third segment of each cirrus is noticeably constricted centrally, and the following in- 

 crease slightly in diameter from the center toward each end, this feature becoming 

 obsolete after the middle of the cirrus. In their distal halves the cirri are somewhat 

 flattened laterally, and in lateral view the segments have almost straight sides. 



Sometimes there are a few cirri near the dorsal pole which are only about half 

 the length of the cirri described, and in which all the component segments are short. 



The disk is either naked, or bears a few plates on and about the anal tube. The 

 sacculi are small and few in number. 



The distal borders of the radials are usually even with the edge of the centrodorsal, 

 or project slightly beyond it. The anterolateral angles of the radials are separated 

 by a notch. 



