438 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



narrow, well rounded dorsally, and widely separated. The following division series 

 are, with some exceptions, 2 (1 + 2); VIIBr series are often and VIIIBr series some- 

 times present. The IIBr axillaries each bear 2 IIIBr 2 (1+2) series. The IIIBr 

 and all following axillaries bear typically a further division series on one face and 

 an undivided arm on the other, the relative position of the two derivatives alternating 

 on successive axillaries, so that at first sight it appears as if each IIBr axillary gave 

 rise to 2 stout arm trunks giving off on every other ossicle branches on alternate 

 sides, the first being always external, and finally ending in a pair of arms. Division 

 series developed where typically there would be an undivided arm that is, on an 

 axillary face adjacent to one carrying a IVBr or later division series are almost 

 always 4 (3 + 4). 



One of the posterior radials, together with the postradial series which it bears, 

 is often smaller than the others, and may be scarcely half as large, as in the case 

 of the type specimen. 



The arms in the type are about 150 in number and about 150 mm. in length. 

 They are composed of about 150 brachials, most of which are short, very obliquely 

 wedge-shaped, with produced and very spinous distal ends. 



Syzygies occur between brachials 1 + 2, sometimes also between brachials 3 + 4, 

 again from between brachials 11 + 12 to between brachials 13 + 14, and distally at 

 intervals of 3 or 4 muscular articulations. 



P D is very long and slender, and is composed of very numerous short segments. 

 P! is similar but much smaller, and the next few are of decreasing length, after which 

 there is but little increase. The lowest pinnules have a well-defined comb which 

 extends to about the twelfth brachial and reappears on more or fewer of the distal 

 pinnules. The segments of the middle and later pinnules are very spiny. 



The color in alcohol is dark brown. 



The preceding description is adapted, with but little change, from Carpenter's 

 original account of the type specimen. 



Notes. The specimen from the Andaman Islands is rather small, with about 

 160 arms which are 90 mm. long. It agrees with others from the Philippine Islands. 



The specimen from Siboga station 316 is typical. There are between 140 and 

 150 arms. One of the IBr series is 6 (5 + 6). The cirri are XVI, 14-15. 



The Challenger specimen from Banda is exactly like the large specimens from 

 the Philippines. 



The specimen from Siboga station 240 (Banda) is small and very badly broken. 



The example from the Macclesfield Bank has about 150 arms. The cirri are 

 XVII, 13-15. 



Abnormal specimen. The example from Siboga station 316 has one of the 

 IBr series 6 (5 + 6). 



Localities. Investigator; Andaman Islands [A. H. Clark, 1912] (1, U.S.N.M., 

 35967). PL 46, fig. 142. 



Siboga station 316; near the Paternoster Islands, north of Sumbava (lat. 7 19' 

 24" S., long. 116 49' 30" E.); 538 meters; fine dark-brown sandy mud; February 

 19, 1900 [A. H. Clark, 1918] (1, Amsterdam Mus.). 



Challenger; Banda; 31 meters [P. H. Carpenter, 1888; A. H. Clark, 1913] 

 (1,B. M.). 



