PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 73 



opposing spine which rises to a height of half the width of the segment. The terminal 

 claw is curved, and somewhat longer than the penultimate segment. 



The radials and more or less, sometimes nearly all, of the IB^ are concealed by 

 the centrodorsal. The IBr 2 (axillaries) are rhombic, entirely free laterally, a third 

 again as broad as long, rising on their posterior border to a slight synarthrial tubercle. 



The 10 arms are from 25 to 60 mm. (usually between 30 and 45 mm.) in length, 

 with a smooth dorsal profile. The first brachials are very short and not at all, or only 

 just, in contact with the ones on the adjacent arms interiorlj'. The second brachials 

 arc considerably larger, irregularly quadrate in form, rising on the proximal border to 

 a small posteriorly directed synarthrial tubercle. The distance between the inner 

 edges of the second brachials of each arm pair equals half the width of the arms. The 

 first syzygial pairs (composed of the third and fourth brachials) and the following five 

 brachials are approximately oblong. The succeeding brachials are almost triangular, 

 usually not much longer than broad, and on the longer side slightly overlap the bases 

 of those following. The outer brachials become more wedge-shaped and then oblong 

 and finally elongated. The syzygial pairs are long. 



Syzygies occur between brachials 3+4, 9 + 10, 14 + 15, and distally at intervals of 

 3 muscular articulations. 



P! and P 2 are similar, verj^ short, from 2.5 mm. to 3.0 mm. long, composed of 8-11 

 (usually 8 or 9) segments of which the first two are usual!}- about as long as broad and 

 the remainder are much elongated. These two pinnules are usually of the same length, 

 but P 2 may be slightly shorter than PI. P a is similar, but usually slightly smaller. 

 P b is commonly similar to P, but may be slightly longer. P 3 and P c are much longer 

 and stouter than the preceding pinnules, from 5 to 7 mm. in length, composed of 13 to 

 16 segments and bearing a well developed gonad. P 4 is much shorter than P 8 , about 

 3.7 mm. in length with 12 segments. The distal pinnules are from 5 mm. to almost 

 7 mm. in length, with 15 to 17 segments. The proximal pinnules are almost smooth. 



The disk is pentagonal, 5 mm. in diameter, without visible calcareous concretions. 

 Sacculi are present on the disk, arms and pinnules, crowded on the last mentioned. 



The color in life is recorded as light brown, or purplish black with light brown 

 cirri. 



The color in alcohol is given as (a) white, banded across the base of each brachial 

 and pinnular with dark purple, the cirri faintly pinkish with a narrow band of light 

 purple at the base of each segment; (6) nearly white, the articulations of the braclmils, 

 pinnulars and cirrals banded with dark brown; (c) white, with crowded small spots of 

 violet brown, the soft parts olive brown; similar, with smaller spots so that the indi- 

 vidual appears lighter; (d) whitish, with broad transverse bands on the brachials and 

 white cirri; (e) violet, the cirri white becoming purple distally; (/) dark brown with 

 the brachial articulations whitish and an obscure longitudinal stripe on the dorsal 

 surface of the arms; (g) uniform dingy grayish brown. 



Localities. Investigator; Andaman Islands; surf line [A. H. Clark, 1912] (1, L.M.). 



Nicobar Islands [A. H. Clark, 1909, 1912] (1, C.M.). 



Singapore [A. H. Clark, 1909, 1912] (7, C.M.). 



Siboga station 144; anchorage north of Salomakiee (Damar) Island, Anambas 

 archipelago; 45 meters; coral bottom and lithothamnion; August 7-9, 1899 [A. H. 

 Clark, 1918] (1, Amsterdam M.). 



