1056 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Genus ASTROCERAMUS, new. 
Type Astroceramus callimorphus, new species. 
Resembles Iconaster Sladen (type Astrogonium longimanum Mobius) in general form, but differs 
in the following respects: Marginal plates centrally beset with rather coarse deciduous granules; third 
superomarginal (at base of ray) conspicuously larger than rest of series; abaetinal plates bordered by 
small, simple granules, not by “very peculiar valve-like plates” (Sladen); actinal intermediate plates 
bear numerous tubercular granules; adambulacral plates of fair size, the furrow armature consisting 
of 5 rather stout, untapered, somewhat compressed, roundly truncate spines which are about as long 
as the furrow margin of the plate. The 2 median spines are slightly the larger, or 4 are subequal and 
nearly parallel. The adoral spine is nearly always conspicuously shorter than the others. On actinal 
surface of plate is a series of 2 stout, blunt, erect, cylindrical, or swollen spines more robust and 
slightly shorter than the furrow series, while on the outer portion of the plate are 7 to 11, stout, 
irregular or thimble-shaped granules, often angular in drying, simulating 2 longitudinal series, 
those nearest the actinal spines largest. Rarely a plate bears a large, two-jawed, spatulate, serrate 
pedicellaria. Similar pedicellarise occur on the actinal intermediate areas. 
It will be seen that this adambulacral armature is considerably different from that of Iconaster, 
whose adambulacral plates are small, the furrow spinelets being small and squamous, and the actinal 
of about the same size and disposed in several series (I. longimanus, Dujardin and Hupe, Hist. Nat. 
des Zooph. Echin., 1862, p. 317, under Astrogonium souleyetii). In Iconaster pentaphyllus (Alcock) 
also the adambulacral plates are small, with a semicircular furrow series of 10 or 11 small foliaceous 
spinelets in the basal half of ray and 8 to 6 in apical half, of which those at ends of series are 
thickened; while actinally there are 3 irregular longitudinal rows of depressed granules. 
The character of the superomarginal plates is, I believe, one of importance. The granules 
surrounding the abaetinal plates ol Astroceramus can not be construed into “very peculiar valvular 
plates,” since they are not plates at all. In Astroceramus the marginal and actinal plates are granular, 
not smooth as in Iconaster. 
Astroceramus callimorphus, new species. 
PI. xxin, figs. 1-3; pi. xxvn, fig. 3. 
Rays 5. R=82 mm.; r=24.5 mm. R=3.35 r. Breadth of ray between second and third supero- 
marginal 15.5-18 mm. ; between third and fourth 12.5-15 mm. 
Rays long and tapering, rigid, fairly slender after the basal expansion is passed; extremities 
pointed. Interbrachial arcs widely rounded. Lateral walls thick and massive, nearly vertical, but 
distinctly concave along the sutural line between upper and lower series of plates. Abaetinal area 
plane; actinal subplane. 
Abaetinal area covered w x ith large, flat, naked plates, irregularly polygonal. Those of radial and 
either adradial series are subcircular or hexagonal in outline, and are more regular than the others. 
Those plates of the interradial triangles are usually irregularly 5- to 6-sided. All decrease in size as 
they recede from the center, the largest plates being those of the primary apical system. All these 
plates are confined to the disk, except 4 or 5 small quadrate plates isolated between superomarginals 
near base of ray. These small plates are separated from one another and alternate with the supero- 
marginals. Abaetinal plates are surrounded by a series of small, oblong or quadrate granules, 
flat-topped and set flush with the general surface. The outer free edge of the granules is sometimes 
rounded. The general surface of plates is plane, or very slightly convex, free from granules, but 
roughened by minute bosses. In spaces between the plates small papulae may be seen, although 
they are absent from a small triangular interradial area (the outer side of which is bounded by the 
interradial pair of superomarginal plates). 
Marginal plates are massive and tumid, the upper and lower series not exactly corresponding on 
the ray. The superomarginals, 19 in number from median interradial line to extremity of arm, are 
much broader than high, and form a wide margin to body. Their outer free angle is abruptly 
rounded, and the length of each plate is about two-thirds to three-fourths the greatest width when 
the animal is viewed from above, but on the outer part of ray the 2 dimensions are nearly equal. 
The plates decrease in size both ways from third superomarginal. Tumid portion of both dorsal and 
lateral surfaces is covered with scattered, low, round granules, which leave a wide, perfectly free area 
