366 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



from Mjoberg's station 3, has the cirri XI, 11-12; empty cirrus sockets occur radially 

 on the centrodorsal. In another, from Mjoberg's station 5, the cirri are X, 10-13; 

 on three-fifths of the periphery of the centrodorsal the cirrus sockets have the fur- 

 purea arrangement, but on the remaining two-fifths they are irregularly placed. In 

 a specimen from Mjoberg's station 12 the cirri are XVIII, 10-12, with the purpurea 

 arrangement on two-fifths of the periphery of the centrodorsal. In another from the 

 same station the cirri are XII, 11-13, with the purpurea arrangement on two-fifths 

 of the periphery of the centrodorsal; 2 of the cirri are small, 1 of these being on 

 either side of a larger cirrus radially placed. 



The 2 specimens from Dundas Strait collected by the Alert and the 1 from 

 Dimes Island, New Guinea, in the British Museum are small. 



In the 13 specimens from the Murray Islands in the collection of the Australian 

 Museum, the cirri are V-X (usually nearer the latter), 9-12 (usually 11-12), 6 mm. 

 long. As in C. pectinata the cirri are of two types which are quite distinct, a general- 

 ized type in which the segments, except the basal two, are subequal in length and 

 the distal are not compressed laterally, and a more speciahzed type in which the 

 distal segments are shorter than the proximal and are laterally compressed. The 

 arms are from 40 to 50 mm. in length. The mediodorsal line from the sixth brachial 

 outward is occupied by a delicate narrow rounded ridge which is more prominent 

 than the similar ridge often seen in C. pectinata. 



Of this species as he found it at Mer in the Murray Islands Dr. Hubert Lyman 

 Clark said that the adults are readily distinguishable from individuals of pectinata of 

 the same size by the characteristic number and arrangement of the cirri. He saw no 

 specimen that could not promptly be assigned to one species or the other by this 

 feature alone, but he failed to find any other difference between purpurea and pecti- 

 nata, and does not feel at all certain that they are really distinct. The fact that speci- 

 mens of pectinata, large and small, were found at Mer associated with purpurea and 

 distinguishable only by their more numerous and more continuously arranged cirri 

 made him somewhat skeptical. Some of the largest specimens of purpurea lack cirri 

 altogether, but the sockets, usually paired, sometimes single, at the five corners only 

 of the centrodorsal are unmistakable. 



The 2 specimens from off Ellison reef are rather large, with the anterior arms 

 125 mm. long. Dr. H. L. Clark says that they look like pectinata, but have the cirri 

 as in purpurea. 



The specimen from the outer Great Barrier reef is smaller than the preceding, 

 quite stout, with all the arms subequal. The cirri are II. The color is a bright 

 orange brown (rust color), but Doctor Clark says that this coloration has the appear- 

 ance of being artificial. 



The specimen from Port Denison has the arms 80 mm. long and the cirri VIII, 

 10-12, from 8 to 10 mm. long. 



The example without locality in the Australian Museum has the arms 120 mm. 

 long and the cirri VII, 14-15, from 9 to 11 mm. long. 



Abnormal specimens. — A 4-rayed specimen from Siboga station 273 has the 

 anterior arms 70 mm. long and the posterior arms 45 mm. long. The cirri are VI, 

 four arranged in two interradial pairs and the others occurring singly. The anterior 



