STARFISHES OF THE PHILIPPINE SEAS. 525 



Genus ASTROSTEPHANE Fisher. 



Astrostci)hane Fisher, 1917/, pp. 421, 422, figs. 3 and 4. Type. Brisvnga 

 moluccana Fisher. 



Diagnosis. — Differing from typical Binsinga in having but 2 

 gonads to a ray, and the proximal adambulacral plates longer than 

 high, as in BnsingeUa. In appearance, especially that of rays, closely 

 resembling Brisingella.^ 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 mar- 

 ginal plates, as in Btisinga^ C rater ohrisinga^ Brisingenes^ and Stegno- 

 brisinga; in having very prominent suboral spines bent at the base 

 so that they extend horizontally into the actinostome. A nonmuscu- 

 lar 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; intercostal integument without 

 spinelets and rather delicate; only 1 subambulacral spine; gonads 

 large, with numerous lobes emptying by a single aperture just above 

 the ambulacral 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 Brisingella than to B^'isinga. 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 {Brisingella^ Astrolirus) or 

 united (Brisinga, Craterohrisinga., Stegnohrising a., Astrostephane) , 

 is dependent upon the number of rays, it may be stated that A. 

 acanthogenys., with 11 rays, has the plates as tightly joined as A. 

 moluccana, with 16 rays. In Brisingella, where this interradial pair 

 of adambulacrals is separated by the outer end of the combined 

 mouth plates, so that they do not touch by the lateral faces, the first 

 marginal plates have a different relation, also. They form a ^ 

 with the unpaired interradial plate, each arm being applied to the 

 upper edge of the first adambulacral plate, and the angle of the /^ 

 being that of the interradius. In Crateroh rising a alherti (Hawaiian 

 Islands), which has 9 rays (less than in Brisingella fragilis). the 

 mouth plates do not separate the first or interradial pair of adambu- 

 lacrals as might be expected if the number of raj^s only determined 

 the characteristic structure of the interradial angle of Bns'mgeTla. 

 The proximal part of the plates in alberti are normally joined, and 

 the closely apposed jSrst pair of marginals has slipped down between 

 the outer ends of the adambulacrals, cementing firmly the ring of 

 plates. There is no hint of the separation of the marginals to form 

 the /^ of Brisingella. 



