180 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



following rapidly increase in length, becoming very elongate distally. P, is about 

 10 mm. long, much longer and considerably stouter than any of the other pinnules, 

 with 12-20 segments of which the basal 2 are about as long as broad and the remainder 

 are elongate, though not more than twice as long as broad; the distal ends of the seg- 

 ments overlap somewhat, especially dorsally, and are furnished with numerous fine 

 spines. Pj is about as long as P, ; the segments, which basally are about as long as 

 broad, become progressively elongated, but the length does not exceed twice the 

 width. P4 and the following pinnules are short, about 3.5 mm. long, and very slender; 

 the basal 4 or 5 segments are about as long as broad and the following gradually 

 increase in length. Distally the pinnules gradually increase in length, the distal 

 pinnules being 9 mm. or 10 mm. long and very slender, with the first segment not 

 so long as broad, the second about as long as broad, and the remainder becoming 

 progressively elongated. The lower and middle pinnules have the distal edges of the 

 segments armed with small spines, but this feature becomes less prominent on the 

 distal pinnules. 



The color in alcohol is whitish, the brachials broadly edged with deep reddish 

 brown. The IBr series and proximal 6 or 7 brachials are purple with a broad median 

 band of white. The lower pinnules are white, reddish purple, or banded, the distal 

 pinnules usually purplish or reddish brown. The cirri are light purplish. 



Notes. — Gisl^n described his Prometra perplexa from Mortensen's station 10 in 

 the following terms: The centrodorsal is discoidal, 2 mm. in diameter, with the bare 

 dorsal pole 1.1 mm. in diameter, flattened with some low and indistinct tubercles. The 

 cirri are arranged in one and a partial second marginal rows. The cirri are XXII, 

 20-26, 13.5 mm. long. The three first segments are broader than long, the fourth is 

 about as long as broad, and those following are similar. From the fifth onward the 

 segments bear a dorsal arched transverse ridge which in lateral view appears as a 

 dorsal spine with a small prominence proximal to it (about the sixth-ninth segments). 

 From about the fourteenth segment there is a simple dorsal spine compressed laterally 

 so as to form a longitudinal crest. The opposing spine is long and sharp, in height 

 equal to about two-thirds the width of the penultimate segment. The terminal claw 

 is as long as, or slightly longer than, the penultimate segment and is weakly curved. 

 The radials are visible as narrow bands about six times as broad as long beyond the rim 

 of the centrodorsal. The IBr, are twice as broad as long, free laterally, and forming 

 with the axillary a weak synarthrial prominence. The 10 arms are 80 mm. long. The 

 proximal portion of the arms is smooth or inconspicuously swollen at the articulations. 

 Syzygies occur between brachials 3 + 4,9 + 10, and distally at intervals of 3 or 4 muscu- 

 lar articulations. Pj is smooth, from 4.5 to 5.8 mm. long, with 14-17 segments. Pj is 

 from 6.8 to 8 mm. long with 16-19 segments of which the longest are twice as long as 

 broad. From the fourth onward the segments have the distal ends slightly expanded 

 and provided with a spiny crown. P3 is about 4.5 mm. long with 13 or 14 segments. 

 P» is lacking. The diameter of the disk is 4.5 mm. The color is whitish with closely 

 set violet spots. 



In another specimen from the same locality, as described by Gislen, the cirri are 

 XXV, 12-19, 3.5 to 7.5 mm. long. The longest segments are only very slightly longer 

 than broad. From the second segment onward there is a stout transverse ridge which 

 on about the eleventh is transformed into a dorsal spine. The 10 arms are from 30 to 



