446 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



not to C. distincta for the reason that the IIIBr series are developed externally as 

 well as internally, both occurring on the same IIBr series. In C. distincta external 

 IIIBr series are very exceptional. 



Professor Bell's original description of Antedon brevicirra, which he assigned to 

 the Spinifera group of Antedon, was as follows: 



Bidistichate, with flattened sides to bracliials, 25 cirri of 9 joints, rather 



more than 40 arms, and a long first pinnule. 

 Colour light brown. 

 Macclesfield Bank, 20-35 fms. 

 This species is so much broken that I should not have described it did I not 



wish to call attention to the short cirri set at the edge of the disc, recalling in 



every way the cirri of an Adinometra. 



The specimen from Macclesfield Bank which served Professor Bell as the type 

 of his Antedon brevicirra is small with numerous cirri and about 45 arms. The one 

 recorded by Bell as Actinometra pari-icirra, which has no indication of the depth at 

 which it was taken, has between 35 and 40 arms. 



The 4 specimens secured in Sagami Bay by Dr. Th. Mortensen show the following 

 characters : 



The centrodorsal is a rounded pentagon 4.2 mm. in diameter. The cirri are 

 arranged in 2 rows. The cirri are XXI, 11,8 mm. long. The fourth cirrus segment 

 is the longest, twice as long as the median width. The 38 + arms are 90 mm. long. 

 Gisl^n says that there were probably 41 arms in life. Of the 10 IIBr series 5 are 

 4 (3+4) and 5 are 2. The IIIBr series are 2 in 12 cases, and 4 (3 + 4) in 1 case. 

 The arms, and especially the pinnules, are very spiny. The first arm syzygy is 

 between brachials 1+2, and the second at about brachials 10+11. Pd bears a comb 

 with 6-8 teeth. Pinnules with combs consisting of about 8 teeth occur here and 

 there to about the thirtieth pinnule. The mouth is central. 



The cirri are about XX, 11. The 38 arms are from 55 to 80 mm. in length. All 

 of the IIBr series are 4 (3 + 4). All of the 1 1 IIIBr series are 2, and all but 1 of them 

 are internally developed. 



The cirri are XXIII, 12, 8 mm. long. The 29+ (probably 33) arms are from 

 40 to 60 mm. in length. The division series are as in the preceding specimen. 



The cirri are XVIII, 10-11, from 6 to 7 mm. long. The arms are 6 + 6 + 5 + 5, 

 with one ray broken, and thus probably 27 in the complete specimen; they are from 

 45 to 55 mm. long. The IIBr series are 2 in 5 cases, and 4 (3 + 4) in 3 cases. The 

 6 IIIBr series are all 2. The combs extend to about the thirteenth brachial. This is 

 a rather young specimen. 



Localities. — Investigator station 225; Andaman Islands (lat. 14° 38' 15" N., 

 long. 96° 24' 30" E.); 97 meters; soft mud; March 24, 1897 [A. H. Clark, 1909, 

 1912] (12, U.S.N.M., 35047, 36200; I. M.). PI. 29, figs. 84-86. 



Investigator; Andaman Islands [A. H. Clark, 1912] (1, I. M.). 



Danish expedition to the Kei Islands; Dr. Th. Mortensen; station 90; Sebesi 

 Strait, between Sumatra and Java; 36 meters; hard bottom; August 1, 1922 (1). 



