134 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



long, those following becoming triangular, not quite so long as broad, in the outer 

 portion of the arm wedge-shaped and about as long as broad, and in the terminal 

 portion elongated. All the brachials are evenly rounded dorsally with projecting 

 distal edges which are armed with line spines. 



Syzygies occur between brachials 3+4, again between brachials 9+ 10 (more rarely 

 10-}- 11), and distally at intervals of 4-8 muscular articulations, the former being the 

 usual number in the distal portion of the arms. In the two arms arising from the 

 single Illir scries there are in both syzygies between brachials 3 + 4 and 15+16, at 

 u lmli point one of the arms is broken off. In the other the following syzygies are 

 distributed first at intervals of from 5 to 8 muscular articulations, soon becoming 

 pretty uniformly 4 as in the arms arising from the IBr auxiliaries. 



P D is similar to Pi, 8 mm. long, slender and flagellate, composed of about 30 seg- 

 ments all of which are about as long as broad with the corners cut away; the second- 

 fourth are furnished with thin rounded dorsal keels. The whole pinnule has an 

 appearance recalling that of the oral pinnules in Heliometra. P 2 is 11-15 mm. long, 

 flagellate, considerably stouter than l\ but resembling it in general proportions; it 

 is composed of 35-40 segments, which are about as long as broad, the first two or 

 three with thin rounded dorsal keels. P 3 and P 4 are similar, stouter than P 2 , 12-16 

 mm. in length, composed of short segments like the preceding pinnules, but with 

 the carination of the basal segments less marked. The succeeding pinnules gradu- 

 ally become shorter and less stout, reaching a minimum about the tenth or twelfth, 

 after which they become still more slender and slowly increase in length. The distal 

 pinnules are 12 mm. long, with about 35 segments, of which the first is trapezoidal 

 and not so long as broad, the second is similar but rather longer, and the remainder 

 are about twice as long as broad or rather longer with somewhat abruptly expanded 

 articulations. The segments of all but the distal pinnules have prominent distal 

 ends which are fringed with fine spines. 



The color in alcohol is uniform yellowish brown. 



Notes. — In the specimen from Mortensen's station 2 as described by Gisldn the 

 centrodorsal is discoidal, 5.2 mm. in diameter, with the bare dorsal pole 4.8 mm. in 

 diameter. The cirri are XXXVI, 15-19, from 11 to 16 mm. long. In the longest 

 eirrus segments the ventral length is about equal to the width. The opposingspine 

 is indistinct. The 14 arms are 125 mm. long. The IIBr series are 4(3 + 4). The 

 IBr, are parti; visible. There is a synarthrial tubercle on the articulation between 

 the two outer elements of the IIBr series, and another on tho articulation between the 

 first two brachials. The distal intersyzygial interval is five or six muscular articula- 

 tions. P, is 9.5 mm. long, with 32 segments. P 2 is 7 mm. long, with 28 segments. 

 Pi is 7 mm. long, with 23 segments. Tho distal pinnules are 8.5 mm. long, with 

 about 22 Begments. P d is 10 mm long, with 25 segments; and P„ is 11 mm. long, 

 with 27 segments. The basal segments of the proximal pinnules have inconspicuous 

 flanges. Gislen said that this specimen differs from tho type as described only in 

 the slightly shorter P 3 , which has fewer segments. 



In one of the specimens from Mortensen's station 10 the centrodorsal is 6 mm. 

 in diameter. The cirri are XXXVIII, 15-19, from 9 to 15 mm. in length. The 11 

 arms are about 100 mm. long. The single IIBr series, which is developed on the 

 right side of a ray, is 4(3+4). P, is 6 mm. long, with 25 segments. P 2 is 8.5 mm. 



