96 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The outer cirrus segments are very slightly broader than long. The arms are about 

 75 mm. long. 



Another specimen has the arms 65 mm. long. PI is 4.5 mm. long with 15 seg- 

 ments. P 2 is 5 or 6 mm. long with 18 perfectly smooth segments. Both of these 

 pinnules are rather strongly prismatic. P 3 is slightly shorter than P 2 , though other- 

 wise similar to it. The following pinnules are shorter and more slender, but stiffened. 

 The cirri are XXIII, 20-22, 12 mm, long. The outer cirrus segments are about as 

 long as broad, or very slightly broader than long. 



The other four specimens are essentially similar to the latter, but in one of them 

 P a is absent on all the arms. 



In the specimen from Mortensen's station 17, as described by Gisle'n, the cirri 

 are XIV, 21-22, from 7 to 9 mm. long. They are arranged in a single row on the 

 centrodorsal. Most of the cirrus segments are broader than long, only in some 

 cirri the most distal segments become as long as broad. A transverse ridge is 

 developed from the third segment onward, later a double spine. 



The 10 arms are 70 mm. long. Weak synarthrial tubercles are present. The 

 distal intersyzygial interval is 4 or 5 muscular articulations. 



P! is from 2.6 to 3.2 mm. long with 9-11 segments. P 2 is from 4 to 5 mm. long 

 with 10-12 segments. P 3 is from 3.2 to 3.5 mm. long with 9 or 10 segments. Espe- 

 cially P 2 is stout, stiffened, and almost smooth. At the distal ends of the distal pin- 

 nule segments there is, however, sometimes very insignificant ornamentation. The 

 longest segments are from one-half to three-quarters again as long as broad. P a is 

 absent hi 7 cases. 



The disk is from 2.5 to 4 mm. in diameter, strongly incised, and without granules. 



The cirri are uniformly bright brown. The arms are banded with white and 

 purple. The distal pinnules have purple spots. 



Gisle'n said that although the cirri are arranged in a single crowded row only, and 

 the arms are nearly twice as long as in the type specimen, this specimen most prob- 

 ably belongs to Oligometra japonica. The cirrus segments are unusually short, thus 

 approaching those in the genus Decametra, but they agree rather well with the 

 original description. 



Gisle'n remarked that this specimen resembles rather closely a specimen in the 

 Upsala Museum that he had referred to Decametra mylitta (see page 188), but in the 

 latter the cirrus segments are still shorter, in the longest distal segments the length 

 being rarely more than two-thirds or three-fourths of the width. 



Localities. Near Misaki, Sagami Bay, Japan; 10-15 meters; Prof. Franz Doflein, 

 October 11, 1904 (6, U.S.N.M., 35772; Munich Mus. [original No. 293]). 



Mortensen's station 17; Misaki, Sagami Bay, Japan; off the Biological Station; 

 46 meters; sand; June 9, 1914 [Gisle'n, 1927]. 



Japan; Dr. Franz Martin Hilgendorf [Hartlaub, 1890, 1891; A. H. Clark, 1907, 

 1908, 1912, 1915, 1918] (1, Berl. M.). 



Geographical range. Southern Japan; definitely known only from Sagami Bay. 



Bathymetrical range. From shallow water down to 46 meters. 



History. This species was first described by Dr. Clemens Hartlaub in 1890 as 

 Antedon japonica from a specimen from Japan that had been collected by Dr. Franz 

 Martin Hilgendorf. It was described by him in greater detail and figured in 1891. 



