306 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



only species listed formally " without doubt," and, second, because the 

 first reviser so fixed it by the simple process of removing the second 

 species from the genus. 



Dorigona is, therefore, a straight synonym of Ogmaster^ and Icon- 

 aster is a tenable name for Astrogonium longimanum. 



l)r. David Starr Jordan concurs in this view. 



Subgenus Glyphodiscus Fisher. 



Glyphodiscus Fisher, 1917c, p. 173. Type, Iconastcr perierctus Fisher. 

 Diagnosis. — Differing from Iconaster s. s. in having conspicu- 

 ously elevated and rough superomarginal plates; a complete series 

 of peripheral granules on the abactinal plates, which, moreover, are 

 perfectly smooth, lacking the tiny blisterlike bosses of Iconastei^; a 

 less compact adambulacral armature. 



ICONASTER PERIERCTUS Fisher. 



Plate 79, fig. 4 ; phTte SI, fig. 3 ; plate 83, figs. 2, 3 ; plate 93, fig. 1, la. 

 Iconaster perierctus Fisher, 1913a, p. 642. 



Diagnosis. — Differing from /. longimanus in having more elevated 

 and rough superomarginals ; all the abactinal plates perfectly smooth 

 and with a complete series of peripheral granules; a less compact 

 adambulacral armature with fewer spines and granules. R=23 mm., 

 r=10 mm., R=2.3 r; breadth of ray at inner end of third supero- 

 marginals, 6 mm., or the length of the first 3 superomarginals meas- 

 ured on ambitus. Superomarginals tabulate, separated by conspicu- 

 ous grooves, the surface having irregular elevations but no granules 

 nor blisterlike minute bosses; beyond the second plate they are 

 imited on the median line of ray; abactinal area sunken, the plates 

 perfectly smooth with a single peripheral series of granules largest 

 on the radial papular areas; peripheral plates tumid, the others 

 slightly swollen, with a plane surface, but not tabulate; plates of 

 center of disk very conspicuously the largest; inferomarginal platey 

 tumid, the first 3 or 4 perfectly smooth, the remainder with slight 

 roughening; actinal intermediate plates in 3 chevrons, smooth, with 

 a single peripheral series of oblong granules; adambulacral plates 

 small, wider than long with 3 or 4 small, stubby, furrow spinelets and 

 following these, 2 shorter, compressed, flat-sided granules, the outer 

 part of the plate being occupied by 4 or 5 small prismatic granules. 



Description. — Abactinal area pentagonal, slightly produced at the 

 corners and sunken below the level of the marginal plates. The 

 plates are perfectly smooth, without the tiny blisterlike elevations 

 of /. longimanus^ Astroceramus, and Lithosoma. Five large hex- 

 agonal plates symmetrically arranged in a quincunx in the inter- 



