418 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



laterally, 10 to 12 times as broad as the median length. The very short lateral 

 borders are strongly convergent, making approximately a right angle with each other. 

 The IBr a (auxiliaries) are triangular, nearly or quite twice as broad as long. The very 

 short lateral sides converge strongly proximally to the anterolateral angles of the 

 I Br,. The anterior edges are rather strongly ooncave. The proximal portion rises 

 to a prominent though broadly rounded synarthrial tubercle. When the animal is 

 viewed in a plane at right angles to the dorsoventral axis the radial portions of the 

 eentrodorsal are seen to have deep V-shaped incisions which make an angle somewlmt 

 greater than a right angle accomodating the IBr,. The IIBr series are 2. The 

 division series and arm bases are rather widely separated laterally. The 14 arms are 

 about 70 mm. long. 



The other specimen from station 3 is an exceedingly small 10-armed individual. 



Remarks. — In describing Antedon spinipinna Hartlaub said that the specimen 

 upon which the description was based is not sexually mature, but nevertheless he 

 felt justified in considering it as a new species because it is so markedly different 

 from the related forms that it is difficult to interpret as a young stage of any one of 

 them. 



He said that spinipinna is a small and very slenderly built form. P, is inter- 

 mediate in character between P! in S. tenuipinna on the one hand and S. spieata 

 mid S. oxyacantha on the other. It is rather stiff and styliform and is composed of 

 about 12 elongated segments, but as in oxyacantha and spieata it is markedly shorter 

 than Pj, which has only 8-10 segments. 



Localities.— Siboga station 81; Pulu Sebangkatan, Borneo Bank; 34 meters; 

 coral bottom and lithothamnion; June 14, 1899 [A. H. Clark, 1918] (1, Amsterdam 

 Mus.). 



Siboga station 89; Pulu Kaniungan ketjil, between northwestern Celebes and 

 Borneo; 11 meters; coral; June 21, 1899 [A. H. Clark, 1918] (1, Amsterdam Mus.). 



Amboina [Hartlaub, 1890, 1891; A. H. Clark, 1907, 1909, 1912, 1918]. 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; Vatek van Toeal; 

 about 2 meters; March 23, 1922 (2). 



Danish Expedition to the Kei Islands; Dr. Th. Mortensen; station 3; 245 meters; 

 March 31, 1922 (2). 



Geographical range. — From Borneo southward to the Moluccas and the Kei 

 Islands. 



Bathymetrical range. — From the shoreline down to 245 meters. 



History. — This species was originally described as Antedon spinipinna by Dr. 

 Clemens Hartlaub in 1890 from a single specimen that had been collected by Dr. 

 J. Brock at Amboina. It was redescribed and figured by him in 1891. I placed it 

 in the new genus Himerometra in 1907 and removed it to Stephanometra in 1909. In 

 1918 I recorded and gave notes upon two specimens that had been dredged by the 

 Siboga at stations 81 and 89. 



STEPHANOMETRA OXYACANTHA (H«rll«nb) 



Plate 47, Figure 217; Plate 48, Figures 218-221 



Anlcdon oxyacantha Hartlaub, Nachr. Ges. G6ttingen, May 1890, p. 178 (description; Amboina); 

 Nova Acta Acad. German., vol. 58, No. 1, 1891, p. 6 (with A. ludovici the most usual species 



