26 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The radials are entirely concealed by the centrodorsal, or their distal coarsely 

 epinous borders are just visible over the ends of the basal rays. The IBri are very 

 narrow, chevron-shaped, with abruptly everted and coarsely spinous edges; they are 

 in close lateral apposition. The IBr 2 (axillaries) are rhombic, twice as broad as long, 

 with the edges concave, and abruptly everted and coarsely spinous all around. There 

 is a high and sharp median keel in the proximal two-thirds. 



The 10 arms are all broken off at the base. The first 2 brachials externally and 

 the second and third internally are sharply flattened laterally. The first brachials are 

 ulteriorly united. The second brachials are large, shield-shaped, deeply incising the 

 very narrow first brachials. The first 2 brachials have more or less everted and 

 coarsely spinous edges. The arms have a very narrow, sharp, and moderately high 

 median carination. 



The pinnules resemble essentially those of S. hana. 



Notes. Of the four specimens from Siboga station 166 one has 10 arms and cirri 

 with 54 segments; another has 13 arms about 60 mm. long and cirri with 49-54 seg- 

 ments, 20-25 mm. long; the other two have 16 and 18 arms. 



The specimen from the Danish Expedition to the Kei Islands station 24 has the 

 cirri XIX, 57-61, about 30 mm. long; there are 13 arms, all broken. The division series 

 and arms have a low and very narrow, though prominent, median keel. 



In my diagnosis of Stenometra acuta from Siboga station 294 I said that this species 

 is most closely related to S. hana of Japan, but it is at once distinguishable from that 

 form by the much shorter cirri which have fewer segments; the carination of the 

 proximal brachials is somewhat sharper and more prominent than in S. hana. The 

 type specimen has the cirri XII, 51-58, 25 mm. long; the first three segments (sometimes 

 also the fourth) bear dorsally a fine median carination ending dis tally in a small spine 

 as in S. hana. The 12 arms are about 60 mm. long. The other specimens from Siboga 

 station 294 are all small with 10 arms. 



Localities. Albatross station 5154; Tawi Tawi Group, Sulu (Jol6) Archipelago; 

 Bakun Point bearing S. 11 W., 0.7 mile distant (lat. 514'50" N., long. 11958'45" 

 E.); 22 meters; coral sand; February 19, 1908 [A. H. Clark, 1909, 1912, 1918] (1, 

 U.S.N.M., 25470). 



Siboga station 166; Ceram Sea (lat. 228'30" S., long. 13103'18" E.) ; 118 meters; 

 hard coarse sand; August 22, 1899 [A. H. Clark, 1918] (4, U.S.N.M., E. 413; Amsterdam 

 Mus.). 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; station 24; Kei Islands; 

 100 meters; April 15, 1922 (1, C. M.). 



Siboga station 294; Timor Sea (lat. 1012'12" S., long. 12427'18" E.); 73 meters; 

 soft mud with very fine sand; January 23, 1900 [A. H. Clark, 1912, 1918] (6, Amsterdam 

 Mus.). 



Port Denison, Queensland [A. H. Clark, 1909, 1911, 1912, 1918] (1, U.S.N.M., 

 17862). 



Geographical range. From the Sulu (Jol6) Archipelago southward to the Ceram 

 and Timor Seas and Port Denison, Queensland. 



Bathymetrical range. From 22 to 118 meters. 



