A MONOGRAPH OF THE EXISTING CRINOIDS 189 



The example from station 53 has 15 arms 140 mm. long. There arc 5 IIBr 

 4 (3 + 4) series. The cirri are XII, 31-32, from 25 to 30 mm. long. 



One of the specimens from station 54 has 18 arms about 80 mm. in length. 

 There are 7 IIBr 4 (3 + 4) series, and a smgle internally developed IIIBr 3 (2 + 3) 

 series. The brachials have very oblique, strongly produced, and very spinous distal 

 edges. Another specimen has 10 arms about 130 mm. long; 7 arms, including 3 

 IIBr series, are just in process of regeneration. The third specimen from this station 

 has 10 arms 65 mm. long. The cirri are XII, 21, 20 mm. long. 



The 2 specimens collected by Dr. H. Merton at the Aru Islands were thus 

 described (as Capillaster clarki) by Reichensperger. 



The centrodorsal is pentagonal, discoidal, with a flat or slightly concave dorsal 

 pole, from 6 to 7 mm. in diameter. The cirrus sockets are arranged in 2 irregular 

 rows. 



The cirri are XXVIII-XXXIV, 20-21, about 15 mm. long, and stout. The 

 first segment is twice as broad as long, the two following are somewhat longer, and 

 the fourth is about as long as broad. The fifth-seventh segments are somewhat 

 longer than broad, the eighth is about as long as broad, and the remainder are all 

 about twice as broad as long. From the eighth onward the segments carry a 

 prominent keel or tooth on the dorsal side. The fifth or sixth is a transition segment. 

 The terminal claw is somewhat longer than the penultimate segment. 



The radials are entirely concealed. The IBrj are partly concealed, short and 

 broad, laterally in contact with their neighbors. The IBr2 (axillaries) are short 

 pentagonal, almost triangular, over twice as broad as long. In the larger specimen 

 the IIBr series are all 4 (3 + 4). The IIBr, is discoidal, about three times as broad 

 as long; the IIBr^ is twice as long externally as internally; the IIBra is very short, 

 and the IIBr4 (axillary) is also short, low triangular. 



The arms are 27-35 in number, from 85 to 100 mm. long. They are of moder- 

 ately well rounded form and first begin to taper rapidly in the outer half. In the 

 larger specimen all the IIIBr series are 3 (2 + 3). The first segments following each 

 axillary are almost wholly united. The first brachial is relatively long, almost 

 square, but somewhat longer externally than internally. The second and third 

 brachials are short discoidal, together slightly shorter than the first. The fourth 

 brachial is similar to the second and third together. On the fifth the brachials 

 begin to become wedge-shaped with strongly overlapping distal ends. In the distal 

 third of the arms the brachials become smoother and also again more discoidal. The 

 produced distal ends are mostly beset with very fine spines. 



Pd is 20 mm. long and is composed of about 42 segments of which the first 12 

 are broad, in part twice as broad as long, and the remainder are about as long as 

 broad. The poorly developed comb is composed of rounded triangular teeth and 

 extends over from 6 to 8 segments. Pj is 1 6 mm. long and is composed of 36 segments. 

 P2 is 10 mm. long with 28-30 segments, and P3 is only 6 mm. long with 20 segments. 

 Pi and P2 resemble Pd in structure. P3 is very slender. The succeeding pinnules 

 quickly become broader and longer and the distal pinnules are 9 to 10 mm. in length. 



The diameter of the disk is about 20 mm. The mouth is interradial. 



