ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS FISHER 5 



fci Disk plates large, with one to three fairly large acicular spines; a vertical series of about 

 four conspicuous, lateral spines to each successive skeletal arch of the rays (of which there 

 are 9 or 10 well-spaced complete ones, confined to basal fourth of ray), these lateral 

 combs occurring at regular intervals all along side of ray; integument between costae 

 has spaced embryonic platelets of various sizes and irregular outline, invisible until 

 dry; adambulacral plates short without furrow spinelets; subambulacral spine with a 

 modified, capitate, truncate tip throughout costal region; syzygy between first and second 

 adambulacral plates; first pair of adambulacral plates and sometimes most of second 

 pair united interradiallv; in young specimens the united pair of conspicuous first marginals 

 normally above the first pair of adambulacrals, may drop between the distal ends of 

 latter, as normally in Brisinga; mouth plates expanded fanwise toward actinostome, 

 nearly closing entrance to ambulacral furrow; gonads in a series of eight or nine, proxi- 

 mally just above adambulacral plates; related to Odinia. Genotype Brisingasler 



robillardi de Loriol Brisingasler de Loriol.' 



b2 Disk plates small, bearing one to several small spinelets; on the ray only one lateral or 

 marginal spine corresponding to the variably spaced inferomarginal plates; never a 

 vertical comb of conspicuous lateral spines. 

 c>. First and second adambulacral plates as well as the upper part of the second and tlnrd 

 ambulacral plates united by syzygy (nonmuscular symphysis). 

 di Abactinal skeleton of ravs in the form of independent, spaced arches or costae composed 

 of elongate, more or less compressed, overlapping plates, projecting well above the 

 level of the intervening integument and bearing small spinelets; intercostal integu- 

 ment not fortified by thin, immersed, spineless, fenestrated plates. 

 e> Gonads numerous, in a series along either side of each ray; at least the first pair of 

 adambulacral plates is joined by their lateral faces, and above them is a umted. 

 pair of first marginal plates — four in all. 

 p Subambulacral spines of proximal adambulacral plates slender, acicular; the acces- 

 sory subambulacral spine, if present, is on the adoral half of the plate; adambu- 

 lacral armature is not dense and crowded. Genotype Brisinga endecacnemos 



Asbj0rnsen Brisinga Asbj0rnsen 



p Subambulacral spines of proximal adambulacral plates with modified, capitate, 

 often truncate, tips; second subambulacral spine regularly present, prominent, 

 and near aboral end of plate; adambulacral plates short, with crowded armature; 

 second and third pairs of adambulacral plates sometimes united interradiallv. 



Genotvpe Brisinga panopla Fisher Craterobrisinga Fisher 



e\ Gonads two to each ray (one on each side); subambulacral spines all delicate and 



acicular. . , 



p The interradial (first) pair of adambulacral plates is joined by their lateral faces, 

 and above them, a united pair of first marginal plates— four in all. Genotype 



Brisinga moluccana Fisher Astrostephane Fisher. 



P The interradial (first) pair of adambulacral plates is not joined, but separate, the 

 outer end of the combined mouth plates usually interpolated between the inner 

 ends of these adambulacral plates; first pair of marginal plates not closely 

 united by their lateral faces, but only by the adoral ends, to which also is closely 

 united the lower end of the interradial plate, forming a rude inverted Y, of 

 which the angle is the apex of the interbrachial angle and the arms are the first 

 marginal plates; adambulacral plates slender with delicate subambulacral spine; 

 ravs delicate, very deciduous. Genotype, Brisinga fragilis Fisher. 



Brisingclla Fisher. 



. I have examined specimens in the British Museum sine* my first keys were published (Ann. and Mag. Hist., ser. 8, 

 vol. 20, 1917, P- 419; Bull. U. S. Nat. Mus. 100, vol. 3, 1919, p. 502). 



