ASTEROIDEA 



85 



lacral plates with 6-8 (9) rather slender furrow spines, and outside 

 these some grains arranged more or less distinctly in two longitu- 

 dinal series. The furrow spines are arranged comb-like along 

 the edge of a rounded projection of the adambulacral plate, which 

 joins that of the opposite plate, thus bridging over the ambulacral 

 furrow, each two successive plates having a round space between 

 them. Thus the ambulacral furrow, especially in the outer j^art 

 of the arm, assumes the shape of a series of fairly large, round, 

 well-separated pores. R = ca. 4-5 r. Grows to a size of ca. 

 110 mm. R. Colour in life yellowish -red. 

 Biology and development unknown. 



Fig. 48. — Nymphaster arenatus ; oral and dorsal side. Nat. size. 



In British seas this species is known from off west Ireland 

 from depths of ca. 400-1300 m. (" Flying Fox ", '" Helga ") ; it 

 appears to be fairly common in places. It is further known from 

 the Bay of Biscay to the Canaries. Also known from the West 

 Indies. Bathymetrical distribution ca. 400-2790 m. 



It may be doubted whether it is really identical with Nym- 

 phaster subspinosus (Perrier), which is distinguished by having 

 some spines on the marginal plates in the interradii. A specimen 

 of this form has been found in the Bay of Biscay ; it may there- 

 fore be expected to occur also in the British seas. 



