326 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Diagnostic features. There are no IIIBr series. The brachials are very short, 

 and those in the proximal portion of the arms are unmodified. The cirri are 20-23 

 mm. long with usually 30 segments, of which the longest are about as long as broad and 

 the outer are one-third again as broad as long; the tenth or eleventh and following 

 segments bear long and prominent dorsal spines which begin abruptly. The 19 arms 

 are about 125 mm. long. 



Description. The centrodorsal is thin discoidal, broad, with the flat polar area 

 4 mm. hi diameter. The cirrus sockets are arranged in a single more or less irregular 

 closely crowded marginal row. 



The cirri are XXIII, 29-32 (usually 30), 20-23 mm. in length. The first seg- 

 ment is short and the following gradually increase hi length to the seventh or eighth, 

 which is about as long as broad. The following segments are at first similar, after 

 the eleventh or twelfth very gradually decreasing in length so that the terminal seg- 

 ments are about one-third again as broad as long. The tenth or eleventh (usually 

 the latter) and following segments bear long and prominent dorsal spines which begin 

 abruptly. The cirri do not taper distally. 



The radials are entirely concealed by the centrodorsal. The IBr! are very short, 

 bandlike, in apposition laterally. The IBr 2 (axillaries) are short, two and one-half 

 times as broad as long, with the lateral borders, which are not so long as those of the 

 IBr t , in contact. The IIBr series are 4(3+4). In the type specimen eight IIBr 

 series are present, and the other arms are broken off before the first syzygy. The 

 division series and the first brachials are hi close lateral apposition and are sharply 

 flattened against then* neighbors. The lateral borders of the elements of the division 

 series are slightly produced. The synarthrial tubercles are obsolete. 



The arms hi the type specimen are 19 (?20) in number, apparently about 125 

 mm. in length. The first brachials are short, slightly wedge-shaped, twice as broad 

 as long exteriorly, mteriorly united. The second brachials are slightly larger and 

 more obliquely wedge-shaped. The first syzygial pah- (composed of brachials 3+4) 

 is slightly longer ulteriorly than exteriorly and twice as broad as long ulteriorly. 

 The next four or five brachials are oblong, three tunes as broad as long, those succeed- 

 ing becoming obliquely wedge-shaped, twice as broad as long, then gradually less 

 obliquely wedge-shaped, and after the end of the proximal half of the arms practically 

 oblong and very short. 



P! is 12.5 mm. long, slender, flagellate distally, with 29 segments, which at first 

 are twice as broad as long, becoming about as long as broad on the eighth and nearly 

 twice as long as broad terminally. The second and following segments bear a sharp 

 carinate ridge with the crest parallel to the axis of the pinnule, which gradually 

 becomes less marked, disappearing on the tenth segment. P 2 is 15 mm. long, con- 

 siderably stouter than P x and not tapering so rapidly distally, with 25 segments, 

 which at first are short, becoming about as long as broad on the eighth or tenth, and 

 twice as long as broad terminally. From the fourth segment there runs outward on 

 the outer side of the pinnule just distal to the mediodorsal line a prominent narrow 

 ridge, which continues almost to the tip. There is a similar but less-marked ridge on 

 PI. The second and following segments are rather sharply, but not highly, carinate. 

 P 3 is similar to P 2 , of about the same size, or slightly shorter and smaller. P 4 is 7 

 mm. long, rather stout, though much smaller than P 3 , tapering evenly to the tip, with 



