ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS FISHER 19 



being conspicuously separated and touch the first marginal plates. There are three 

 marginal spinelets to each plate, two on actinostome and one in the furrow separating 

 the first and second tube-feet. The suboral, situated at about the middle of the plate 

 but nearer the furrow than the median suture, is short and slender, a little longer 

 than the width of the actmostomial margin of combined plates. The spinelets bear 

 the usual terminal pads of pedicellariae. In B.jragilis there are generally three 

 actinostomial spinelets and two aboral furrow spinelets. The suboral spine is small 

 and stands in line with the furrow spinelets, forming a diagonal series. In B. pusilla 

 there is usually only one actmostomial spinelet, rarely one aboral spinelet (usually 

 none), and the slender suboral spine is longer than usual in the genus BrisingeUa. 



The articulation surface (distal) of the second ambulacral ossicle (where a ray has 

 been removed) is very small, broadly elliptical, and the combined width of the pair 

 exceeds the height. This character is more like the same in B. pusitta than in B. 

 fragilis, where the distal facets are relatively larger. The first marginal plates are 

 characteristic of the genus in their relation to the adambulacrals and the interradial. 



Type— Cat. No. 37038, U.S.N.M. 



Type-locality.— Station 4767, Bowers Bank, Bering Sea, 54° 12' N., 179° 07' 30" 

 E.; 771 fathoms, green mud; bottom temperature, 36.5° F. 



Remarks. — The synopsis of species will sufficiently indicate differences between 

 this species and the California forms. BrisingeUa coronata (Sars) is not closely related, 

 as it is characterized by a short costal region and only 10 to 14 skeletal arches which 

 do not extend more than 6 r from the base of ray. The adambulacral plates have 

 two adoral furrow spinelets. The species is the largest known in this genus. Sars 

 figures a specimen with a disk 28 mm. in diameter and a ray 320 mm. long, which is 

 large even for a typical Brisinga. 



Genus ASTROSTEPHANE Fisher 



Astrostephane Fisher, Ann. and Mag. Nat. Hist., ser. 8, vol. 20, 1917, p. 421. Type, Brisinga 

 moluccana Fisher; Bull. U. S. Nat. Mus. 100, vol. 3, 1919, p. 525. 



Diagnosis. — Differing from typical Brisinga in having but two gonads to a ray, 

 and the proximal adambulacral plates longer than high, as in BrisingeUa. In appear- 

 ance, especially that of rays, closely resembling BrisingeUa, but differing in having 

 the first adambulacral plate tightly joined for its whole length to that of the adjacent 

 ray, and in having directly above these a closely joined pair of first marginal plates, 

 as in Brisinga and Oraterobrisinga; in having very prominent suboral spines bent at 

 the base so that they extend horizontally into the actinostome. A nonmuscular 

 joint, or syzygy, between the first and second adambulacral plates and between the 

 upper part of the second and third ambulacral plates; costae thin, well spaced; inter- 

 costal integument without spinelets, rather delicate; only one subambulacral spine; 

 gonads large, with numerous lobes emptying by a single aperture just above the ambu- 

 lacral plates a little over 2 r from the base of ray; disk with close-set small spinelets. 



Remarks. — It seems probable that this genus is more nearly related to Bris- 

 ingeUa than to Brisinga. Fortunately there are two very distinct species, so that the 

 characters given in the diagnosis as of generic value are probably reasonably accurate. 



If it is contended that the condition of the interradial pair of adambulacral 

 plates, whether separated (BrisingeUa, Astrolirus) or joined (Brisinga, Oraterobrisinga, 



