STARFISHES OF THE PHILIPPINE SEAS. 503 



2\ Abactinal skeleton of rays in tlie form of independent spaced arches 

 or costae composed of elongate, more or less compressed, over- 

 lapping plates, projectiiig well above the level of the intervening 

 integument and bearing small spinelets; intercostal integument 

 not fortified by thin, immersed, spineless fenestrated plates. 

 f. Gonads numerous, in a series along either side of each ray ; the 

 interradial (first) pair of adambulacral plates is joined by their 

 lateral faces, and above them is a united pair of first marginal 

 plates — four in all. (Figs. 1 and lo, pi. 156.) 

 g^. Subambulacral spines of proximal adambulacral plates slender, 

 acicular; the accessory subambulacral spine, if present, is on 

 the adoral half of the plate; adambulacral armature is 

 not dense and crowded. Genotype, Brisinga endecacnemos 



Asbj0rnsen Brisinga Asbj0rnsen. 



g^. 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 arma- 

 ture. Genotype, Brisinga panopla Fisher. 



Craterobrisinga Fisher. 

 f. Gonads 2 to each ray (one on each side) ; subambulacral spines 

 all delicate and acicular. 

 g". The interradial (first) pair of adambulacral plates is joined by 

 their lateral faces, and above them is a united pair of first 

 marginal plates— 4 in all. (Figs. 2 and 2a, pi. 156.) Geno- 

 type, Brisinga moluccana Fisher Astrostephane Fisher. 



g\ The interradial (first) pair of adambulacral plates is not joined, 

 but separate, the outer end of the combined mouth plates 

 being usually interpolated between the inner ends of these 

 adambulacral plates; first pair of marginal plates is 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 reversed Y, of which the 

 angle is the apex of the interbrachial angle and the arms 

 are the first marginal plates (figs. 3 and 3a, pi. 156) ; adambu- 

 lacral plates slender, with delicate subambulacral spine ; rays 

 delicate, very deciduous. Genotype, Brisinga fragiUs Fisher. 



Brisingella Fisher. 

 '. Abactinal skeleton of rays consisting of independent compressed 

 arches or costae as in Brisinga, but the integument between the 

 arches is crowded with numerous, spineless, immersed, fenes- 

 trated, thin plates, sometimes slightly overlapping, yet leaving 

 the integument quite flexible ; gonads 2 or 4 to each ray. 

 f. First pair of adambulacral plates united, and joined to their 

 upper side is a united pair of marginal plates, 4 in all, as in 

 Brisinga; proximal adambulacral plates higher than long; 

 gonads 2 to each ray. Genotype, Brisinga (Stegnobrisinga) 



placoderma Fislier Stegnobrisinga Fisher. 



f. First pair of adambulacral plates not joined together by their 

 lateral faces, but separate; first pair of marginal plates is 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 



