SUPPLEMENT TO 

 ECHINODERMATA. 



By Hedley L. Coleman. 



(Plate Ixxxiii., and figs. 123-125.) 

 In the Report on the "Thetis" Echinodermsi Prof. H. L. Clark 

 referred two specimens of a fine large Asteroid to Nectria ocelli- 

 fera, Lamk. Subsequent to the publication of his paper, he 

 found that a mistake had been made. He therefore wrote to the 

 Curator of this Museum pointing out that the specimens in 

 question really constituted a new species of the genus Astero- 

 discus, Gray. ; at the same time suggesting that 1 should describe 

 it. For this compliment I wish to tender my grateful acknowledg- 

 ment. 



ASTERODISCUS TRUNCATUS, sp. nov. 



(Plate Ixxxiii. and figs. 123-125.) 



Nectria ocellifera, H. L. Clark, Mem. Austr. Mus., iv., 1909, 

 p. 529 (non Lamk.) 



Rays 5. R=103mm. ; r=51 mm. R=2r. Breadth of ray 

 at base 50 mm. Disc large and inflated. Rays broad, fairly 

 long, tapering to a blunt extremity ; slightly unequal as to 

 length and breadth. Interbrachial arcs widely rounded. Side 

 of body fairly high, well rounded. Abactinal surface covered with 

 numerous tubercles, having the 

 form of inverted, truncated 

 cones, which are slightly convex 

 at the surface (fig. 123). A 

 median radial line, and an ad- 

 radial series distinguishable, 

 beyond these the tubercles 

 irregular. Each tubercle stands 

 on a prominence of the test, 

 and the larger ones are confined 

 to the disc and bases of the rays. 

 Scattered among the tubercles 

 are large spherical granules, 

 which vary slightly in size. 

 Marginal plates not con- 

 s|ncuous. Corresponding to supermarginals are three ossicles 

 (from interradial line) omitting large ))late at extremity of ray. 



Fig. 12,S. 



1 Austr. Mus. Mem. iv., 1909, p. 529. 



