ASTEROIDEA 



13' 



3. Gastraster Perrier. 



Disk plates not forming a regular rosette. Dorsal plates of 

 arms arranged in very regular longitudinal rows . Lower marginals 

 carry a series of large, flattened spines, forming a conspicuous 

 fringe along sides of arms. Adambulacral plates with two spines. 

 Tube-feet 4-serial in proximal part of arm, biserial farther out. 



Only one species known. 



1 . Gastraster margaritaceus Perrier. 

 Rays 5, somewhat tapering, flattened 



(Fig. 78.) 

 on the under side. 



Dorsal plates of arms each carrying a group of 6-7 short rounded 

 spines, among which isolated crossed pedicellariae occur. In the 

 spaces between the plates single papulae. Marginal spines 



Fig. 78. — Gastraster margaritaceus, oral and dorsal side. Somewhat 

 enlarged. (After Perrier, ^chinod. " Travailleur " et " Talisman ".) 



arranged in oblique series of 3-4, the outer, proximal one being 

 the largest. The adambulacral spines rather long and slender, 

 each two forming a transverse series oblique to the ambulacral 

 furrow. Between the adambulacrals and the marginals some 

 small straight pedicellariae ; such are also found within the 

 ambulacral furrow, especially in the proximal part. Colour in 

 life unknown. Not known of a larger size than 17-5 mm. R. 



Biology and development unknown. 



One small specimen, 12 mm. R., found at 53° 07' N., 14° 50' W., 



