440 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



the brachials become laterally compressed and begin to overlap. This is reduced 

 again in the last few, which diminish rather rapidly in size. 



Syzygies occur between brachials 3+4 and 12 + 13, and distally at intervals of 

 5 or 6 muscular articulations. 



The pinnules are all stiff and styliform and consist of elongated segments. Those 

 of the first pair (Fj and ?») are relatively small, those of the second pair (P2 and Pb) 

 considerably larger. 



The disk and ambulacra are well plated, but the side- and covering-plates are 

 not well differentiated on the pinnules. 



Sacculi are very rare, or absent altogether. 



The color in alcohol is light whitish brown. 



Notes. — The precedmg description is that of Carpenter with the addition of a 

 few notes I made on the type specimen during a visit to the British Museum in 1910. 



In the specimen from Siboga station 260 the centrodorsal is columnal, 5.5 mm. 

 broad at the base and 3 mm. in interradial height. The cirrus sockets are arranged 

 in 10 columns of 2 each. The columns of adjacent radial areas are close together, 

 separated by a slightly marked ii-regular rounded ridge which in width is equal to 

 from one-half to one-third the diameter of the adjacent sockets. The two columns 

 of each radial area are separated in the midradial line by a slightly concave bare 

 space equal m width to about one-half the diameter of a cirrus socket. The dorsal 

 pole is slightly concave and is marked by five large, though low and obscure, tubercles 

 as in the other species of the genus. 



The cirri are about X, 87-98, from 70 to 80 mm. long, moderately slender. The 

 longest proximal cirrus segments are about twice as long as broad. 



The ends of the basal rays are prominent as small tubercles in the angles of the 

 calyx. 



The radials have a prominent median dorsoventrally elongated tubercle. The 

 IBri and the proximal third or half of the axillary bear a narrow low rounded median 

 carination, on the former highest distally, on the latter highest proximally, the high- 

 est points being marked usually by a slight elevation in the genei'al surface. Traces 

 of this are seen on the first two brachials. In some cases there is a tubercle toward 

 the distal border of the IBrj, and a similar tubercle toward the proximal border of 

 the axillary, the latter with faint traces of broad tubercles anterior to and on either 

 side of it; each of the first two brachials also bears a tubercle. 



The 10 arms are 105 mm. long. 



This appears undoubtedly to be an undeveloped individual of A. longicirra. 

 The cirri are more slender than those of the type specimen and are composed of rela- 

 tively longer segments, and the ornamentation of the elements of the IBr series and 

 first two brachials is scarcely more than indicated. 



Localities. — Challenger station 192; near the Kei Islands (lat. 5°49'15" S., long. 

 132°14'15" E.); 256 meters; blue mud, September 26, 1874 [P. H. Carpenter, 1888; 

 Bell, 1893 (part); Hartlaub, 1895; A. H. Clark, 1907, 1909, 1911, 1912, 1913, 1918] 

 (1, B. M.). 



Siboga station 260; 2.3 miles N. 63° W. from the northern point of Nuhu Jaan, 

 Kei Islands (lat. 5°36'30" S. long. 132°55'12" E.); 90 meters; sand, coral, and 

 shells; December 16, 18, 1899 [A. H. Clark, 1918] (1, Amsterdam Mus.). 



