A MONOGRAPH OF THE EXISTING CRINOIDS 153 



long, the second is slightly broader than long, the third is slightly longer than broad, 

 the fifth is twice as long as the median width, and the eighth or ninth and following 

 are about three times as long as broad. The longer segments are very slightly 

 constricted centrally, and the distal ends are slightly prominent and are armed with 

 exceedingly fine spines. 



Locality. Investigator station 534; Mergui Arcliipelago, west of Tavoy Island 

 (lat. 12 59' N., long. 96 48' 30" E.); 110 meters; coral and sand; April 17, 1913 

 (14, U. S. N. M.; I. M.). 



Remarks. This species is more or less intermediate between E. junceus, in which 

 the cirri are greatly elongated, slender, composed of usually 22 greatly elongated 

 segments, and taper gradually from the base to the tip, and the other species of the 

 genus in which the cirri are much shorter and are composed of fewer segments of 

 which the longest are never more than twice as long as broad and the distal are about 

 as long as broad. It seems to be most closely related to E. ornatus from which it 

 differs in having the cirri more slender with more elongated segments, in the longer 

 P a and P 2 , in having the ossicles of the IBr series and the earlier brachials distinctly, 

 though roundedly, carinate, and in having the distal edge of the earlier brachials 

 much less produced. 



EUDIOCBINUS PINNATUS A. H. Clark 



PLATE 11, FIGURE 39 

 [See also vol. 1, pt. 1, fig. 84 (side view), p. 137; pt. 2, fig. 787 (ambulacra! deposits), p. 366.] 



Eudiocrinus pinnatus A. H. CLARK, Proc. Biol. Soc. Washington, vol. 25, 1912, p. 27 (description; 

 Siboga Station 310); Amer. Journ. Sci., vol. 40, 1915, p. 62 (listed); Unstalked crinoids of the 

 iSiboja-Exped., 1918, p. ix (relationship with E. variegatus), p. 64 (in key; range), p. 67 (refer- 

 ences; detailed description; station 310), p. 68, fig. 4, p. 276 (listed), pi. 17, fig. 30. GISLEN, 

 Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 73 (compared with E. loveni). 

 A. H. CLARK, Temminckia, vol. 1, 1936, p. 295 (listed), p. 300 (Snellius station 123*; notes). 



Diagnostic features. The cirri are short and stout, with none of the component 

 segments longer than broad; P a and Po are elongated and stiffened, but slender like 

 the succeeding pinnules and not enlarged, with the third and fourth segments half 

 again as long as broad; these pinnules are one-third or one-fourth again as long as 

 the pinnules following, and are composed of 16 or 17 segments. 



The short, stout, short-segmented cirri distinguish this species from all the others 

 in the genus except E. variegatus and E. loveni. From E. variegatus it is distinguished 

 by the slenderness of P a and P'a, which have longer proximal segments, and from 

 E. loveni it is distinguished by the fact that these pinnules are markedly longer than 

 those succeeding and are composed of 16 or 17 instead of only 11 segments. 



Description. The centrodorsal is discoidal, with the flat dorsal pole 2 mm. in 

 diameter. The cirrus sockets are arranged in two marginal rows. 



The cirri are XVII, 17-22, from 10 to 11 mm. long; all the segments beyond the 

 third are subequal, none being quite so long as broad; the fourth-eighth or -ninth 

 have slightly prominent distal edges, especially dorsaOy. The cirri are rather stout 

 and are of the same type as those of E. variegatus. 



The five arms are about 75 mm. long; the brachials are unormtmented, and their 

 distal edges are not produced. 



20824440 11 



