304 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The 18 arms are probably 110 mm. long and are composed of about 200 short 

 and slightly overlapping brachials. The first brachials are in almost complete con- 

 tact interiorly. The first eight brachials are discoidal and are succeeded by about 

 30 shortly triangular brachials, which are followed by discoidal ones, these continuing 

 to the tip of the arm. The distal ends of the brachials are usually very finely spinous, 

 though not produced. In specimens from the east coast of India they are occasionally 

 slightly produced and rarely considerably produced and everted. 



Syzygies on six arms occur as follows: 



1. Between brachials 3+4, 13 + 14, 21+22, 28+29, 37+38, 47+48, 56+57, 

 65 + 66, and 74 + 75. 



2. Between brachials 3+4, 9 + 10, 14 + 15, 21+22, 29 + 30, 33 + 34, 41+42, 

 49+50, 63 + 64, 72 + 73, 77+78, 84 + 85, and 92 + 93. 



3. Between brachials 3+4, 15 + 16, 25+26, 34+35, and 42+43. 



4. Between brachials 3+4, 15 + 16, 25+26, 35+36, 50+51, and 60 + 61. 



5. Between brachials 3+4, 16+17, 23+24, 31+32, and 38+39. 



6. Between brachials 3+4, 7+8, and 31+32. 



P D is about 10 mm. long and is composed of 31 segments of which the first seven 

 are broad, flattened, and carinate, the later ones gradually becoming cylindrical, 

 longer than broad, and with rounded ends. P! and P 3 are about equal in size, and 

 P a and P resemble them. P l and P 3 have about 29 segments. P 2 and P b are the largest 

 pinnules on the arm, P 2 being about 15 mm. long, but having 27 segments only. The 

 basal segments of the first three pairs of brachial pinnules are flattened and more or 

 less carinate. P 5 and P e are the shortest pinnules, the pinnules succeeding gradually 

 increasing in length. The carination on the basal segments of the earlier pinnules, 

 usually moderate or rather slight, is occasionally much exaggerated. 



The disk is 10 mm. in diameter and is considerably incised. The ambulacra are 

 naked. Sacculi are abundant and closely set on the arms and pinnules, but are 

 absent from the disk. 



In alcohol the disk is chocolate-brown, fading to white in the interambulacral 

 angles. The brachials are pinkish, with the articulations in the proximal fourth of 

 the arms marked with bands of deep reddish brown, which gradually fade into dots 

 on the sides of the arms. The pinnules are irregularly banded with brown and white. 



The preceding description is adapted from Chadwick and is based upon the single 

 specimen secured at the Ceylon Pearl Oyster Fisheries station XXXIV. 



Notes. The two specimens from South Male are both small 10-armed individuals 

 the identity of which must be considered as somewhat doubtful. 



Miiller's description of the type specimen is as follows: The centrodorsal is flat, 

 bearing marginal cirri. The cirri are about XX, 40 ; the segments gradually develop 

 a dorsal tubercle. The radials are visible. The IIBr series are 4(3+4). The 20 

 arms are 4 inches long. The distal intersyzygial interval is usually eight muscular 

 articulations. P 2 and P 3 are longer than the other pinnules. The ventral side of 

 the disk is soft. 



Miiller wrote in his description that there are three radials of which the third is 

 axillary with a syzygy, and the same wording was given by Dujardin and Hup6 in 

 1862. Obviously a part of what he wrote in his manuscript was omitted in the print- 

 ing. What he intended to say was that there are three radials (that is, the radials 



