210 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The distal ends of the radials are approximately even with the rim of the centro- 

 dorsal. The IBr! are short, and are laterally united for their entire length. The 

 IIBr series are 4 (3 + 4). The IIIBr series are 4 (3+4) exteriorly and 2 interiorly. 

 The IVBr series, which are developed only on the inner side of the inner IIIBr series 

 from each IIBr series, are 4 (3+4). Each IIBr series divides once exteriorly and 

 twice interiorly. The division series resemble those of H. martensi. 



The 51 arms of the type specimen are 120 mm. in length and resemble those of 

 H. martensi. 



P D and P P are 25 mm. long, very stout basally but tapering gradually to a slender 

 and delicate tip, with about 40 segments most of which are about as long as broad. 

 PI is 15-17 mm. long, proportionately slenderer than the preceding pinnules, with 

 about 32 segments, which are slightly longer than broad, the first two slightly carinate. 

 P a is smaller and slenderer, 13 mm. long, with 30 segments of which the first is short, 

 the next three or four are about as long as broad, and the remainder are slightly 

 longer than broad; the second, third, and fourth segments are somewhat carinate. 

 P 3 is 8 mm. long, small, and weak, with about 20 segments, of which those in the 

 proximal half are about as long as broad and those in the distal half are slightly longer 

 than broad; the second-sixth are rather strongly carinate. The succeeding pinnules 

 decrease rapidly in length, the fifth and following being 5 mm. long, then slowly 

 increase again, reaching a length of 9 mm. distally. 



Notes. In the specimen from Siboga station 96 the cirri are rather stout, 30 mm. 

 long, with 37-38 segments, of which the longest proximal are from half again to twice 

 as broad as long; there is very little difference between the proximal and distal seg- 

 ments ; from the nineteenth or twentieth segment onward prominent dorsal tubercles 

 or short blunt dorsal spines are developed. The 61 arms are 120 mm, long. Four 

 of the postradial series bear 12 arms each, and the fifth bears 13 arms. Each IIBr 

 series bears externally a IIIBr 4(3+4) series and internally a IIIBr 2 series, which 

 carries two IVBr 4(3+4) series. 



P D is 23 mm. long, with 37 segments, very stout basally but tapering evenly to a 

 slender and flagellate tip. The basal segments are twice as broad as long, those 

 following gradually increasing in length and becoming about as long as broad on the 

 twelfth and half again as long as broad in the delicate terminal portion. The pinnule 

 is perfectly smooth, with no traces of eversion of the distal edges of the segments. 

 P P is 22 mm. long, with 36 segments and is only very slightly smaller than P D . P, is 

 similar to the two preceding pinnules but is somewhat smaller, 17 mm. long. P a is 

 weak and slender, 8.5 mm. long, with 23 segments, of which the second-fifth have a 

 prominent narrow carination the distal border of which is parallel to the longitudinal 

 axis of the segments. P 3 is 6.5 mm. in length, resembling P 2 but very slightly smaller. 

 P 4 is 5.5 mm. long, resembling P 3 but very slightly smaller; the second-fourth segments 

 are carinate. From this point the amount of carination of the earlier segments of the 

 pinnules decreases, though it is traceable to the end of the proximal fourth of the arm. 

 This specimen differs from the type only in the slightly smaller size and in the slightly 

 shorter proximal cirrus segments. 



In the specimen from Singapore the cirri are XII 26-30, 20 mm. long, and rather 

 slender; the segments have rather prominent ends. There are 17 arms 50 mm. long. 

 Four IIBr series are developed of which three are 4(3+4) and one is 2. There are 



