192 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



is very slightly longer than the penultimate segment, moderately stout and mod- 

 erately curved basally, becoming more slender and less curved distally. 



The distal border of the radials is approximately on a level with the run of the 

 centrodorsal. The IB^ are oblong, about three times as broad as long, not in contact 

 basally. The IBr 2 (axillaries) are pentagonal, about twice as broad as long, their 

 lateral borders about half as long as those of the IBrj and making with them a very 

 obtuse angle. The IBr series and lower brachials bear a slightly indicated median 

 carination. 



The 10 arms are 65 mm. long. The first two brachials are approximately equal, 

 wedge-shaped, about twice as broad as their exterior length. The first syzygial pair 

 (composed of brachials 3+4) is oblong, or slightly longer ulteriorly than exteriorly, 

 from half again to twice as broad as long. The next four or five brachials are oblong, 

 about three times as broad as long, those following becoming very obliquely wedge- 

 shaped, almost triangular, half again as broad as long, in the distal portion of the 

 arm less obliquely wedge-shaped and somewhat longer, and in the terminal portion 

 longer than broad. 



Syzygies occur between brachials 3+4, again from between brachials 9 + 10 to 

 between brachials 14 + 15, and distally at intervals of from 4 to 8 (usually 6 or 7) 

 muscular articulations. The second syzygy is occasionally between brachials 5 + 6, 

 and the third may be as far out as between brachials 16 + 17. 



P a is absent. PI is small and weak, 4 mm. long, with 14 segments of which the 

 first is short, the second is squarish, and those following gradually increase in length, 

 becoming twice as long as broad distally; the segments in the distal third have the 

 distal edge armed with fine spines. P 2 is 13 mm. long, stouter than PI though of the 

 same proportions, with 17 segments which become about as long as broad on the third 

 and twice as long as broad terminally; the second and following segments have a 

 few spines on the distal edge. P 3 is 6 mm. long, basally as stout as P 2 but not taper- 

 ing so rapidly and therefore less delicate distally, with 15 segments of which the distal 

 are elongated. P is 4 mm. long, not so delicate as PI, with 10 segments. P 6 is 3 mm. 

 long. The pinnules following increase slowly in length, the distal pinnules being 

 7 mm. long with elongated segments. 



The color in alcohol is brown, the perisome darker. 



Notes. In the 6 specimens' from Kurrachi in the British Museum the cirri are 

 XII-XV, 20-23 (usually 22), 10 mm. long. The dorsal processes on the outer seg- 

 ments are very small. The 10 arms are 65 mm. long. P] has about 13 segments 

 and resembles P 2 , but is usually about 1 mm. shorter and proportionately more 

 slender. P 2 is the largest pinnule, about 5 mm. long; it is slender, and most of its 

 segments are about twice as long as broad, or even longer; the segments number 

 about 14 of which those in the distal half are more or less prismatic and have pro- 

 jecting outer corners. P 3 is very similar to PI. P is shorter, and P 6 is shorter still. 

 Sometimes P] is considerably shorter than P 2 or than P 3 . 



Localities. Investigator; ?Kurrachi [A. H. Clark, 1909, 1912, 1918] (6, I. M.). 



Kurrachi [A. H. Clark, 1913] (6, B. M.). 



Persian Gulf, off Kharg Island, 12.5 meters; sand and stones; Dr. G. Thorson, 

 March 16, 1937 [Mortensen, 1940; Gisle"n, 1940]. 



