424 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 40. 



As in Iconaster the only spines are those of the furrow margin. The 

 animal is hard, smooth, of a stony or porcelain texture, and of con- 

 spicuous size. 



ATELORIAS, new genus. 



Gorriasteridae with unequal marginals, the superomarginals the 

 larger and denning entire angular ambitus; with all the plates gran- 

 ulate, and covered with thin soft membrane leaving each plate dis- 

 tinct; abactinal plates flat, numerous, extending to tip of ray; 

 papulae in radial petaloid areas; adambulacrals with an angular 

 furrow series and subambulacral granules; actinal interradial areas 

 large; disk large, rays slender. Entrenched small upright two- 

 jawed pedicellariae on abactinal, marginal, actinal intermediate, and 

 adambulacral plates. No specialized spines; the furrow spinelets 

 the only ones present. 



Type. — Atelorias anacanthus, new species. 



ATELORIAS ANACANTHUS, new species. 



Rays 5. 11 = 205 mm., r = 43 mm., R = 4.76 r.; breadth of ray at 

 mid interbrachium, 53 mm., at middle of R, 14 mm. Disk large, 

 thin, with wide interbrachial arcs. Rays very long, slender, thin, 

 with an angular margin formed entirely of superomarginal plates. 

 No specialized spines; all plates covered with hemispherical granules 

 immersed in a thin membrane which partly obscures them, and fills 

 up the interstices but which leaves the outlines of plates distinct. 

 Small excavate pedicellarise with two jaws slightly higher than wide, 

 and usually with depressions in the membrane into which they fit 

 when open, are present on plates of both surfaces. 



Abactinal plates numerous, very slightly convex or flat, hexagonal 

 on papular areas but elsewhere irregularly hexagonal, pentagonal, 

 squarish or roundish, and reaching terminal plate. Plates not at all 

 tabulate but sensibly higher on the petaloid radial papular areas; 

 papulae 5 or 6 about each plate, and inconspicuous, not extending far 

 along ray. All plates covered with hemispherical granules, sunken 

 in soft membrane, and with a pedicellaria. 



Superomarginals about 80 to a ray encroaching conspicuously upon 

 abactinal area and with a nearly flat upper surface; throughout wider 

 than long. The}- encroach upon actinal surface about one-half as far 

 as upon abactinal and thus form the margin of ray. The convexity 

 of the lateral angle of plate causes the margin of ray to appear scal- 

 loped except near extremity. Inferomarginals proximally consid- 

 erably wider, and beyond interbrachium only slightly wider than the 

 actinal surface of superomarginals, and entirely actinal in position; 

 surface very slightly convex. Both series with the characteristic 

 granules and pedicellarise. 



