1058 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
• Genus CALLIDERMA Gray. 
Calliderma Gray, Proc. Zool. Soc., 1847, p. 76. Type, C. emma Gray, P. Z. S., 1847, p. 77; Ann. N. H., vol. xx, 1847, p. 198. 
Calliderma spectabilis, new species. 
PI. XXIV, figs. 1,2; pi. xxv, figs. 1-3; pi. XXVI, fig. 3. 
Size large; form pentagonal, the angles prolonged into rays, the outer attenuate portion of which 
is formed by marginal plates only. General form depressed, flattened, abactinal surface subplane to 
slightly convex. Interbrachial arcs are very wide, the interradial portion of the margin of disk being 
straight and passing gradually into the rays, which have thus a broad base and taper rapidly into the 
elongated slender outer portion, the distal 20-26 superomarginal plates of adjacent sides being .in con- 
tact medially. Disk is very large in proportion to rays. R=202 mm.; r=85 mm. 11=2. 37r. 
Marginal plates are well developed, forming a stout border to disk, but relatively not so large as 
in C. emma. Plates of upper and lower series do not exactly correspond in number, nor are they 
exactly opposite, except sometimes for a short distance on either side of the interradial line. Through- 
out most of the ray they are usually alternate, the suture between them having a zigzag course. Edge 
of disk is square-cut on both surfaces, the lateral surface of the plates sloping inward toward the suture 
between the 2 series, so that the lateral face of disk and rays is concave or like a shallow V-shaped 
trough. 
Superomarginal plates are broader than high and about as high as long. In interbrachial arc the 
outer margin of each plate is often slightly shorter than the inner, but the plates are irregular in this 
respect. Surface of plates subplane to slightly convex. There are 90 to 94 to each side of the body 
(more numerous in the largest specimen; 77 in a medium small specimen). General surface is cov- 
ered with numerous, crowded, low, round, flat-topped granules, a marginal series being usually 
distinguishable. Granules of the latter become subconical along the margin adjacent to inferomar- 
ginals, and those of the lateral face of plate are more rounded than on dorsal surface. On the angular 
margin, where lateral and dorsal superficies meet, each plate bears 2 to 4 stout, short, tapering, very 
sharp spinules in a longitudinal series, and they extend along the ray to within 4 or 5 plates of where 
the 2 series of superomarginals meet medially. Throughout rest of ray they are absent. 
Inferomarginals are slightly larger than the superomarginals, and also a little higher, their width 
on the actinal surface being greater than that of the superomarginals on the abactinal. They form a 
raised border to the ventral surface. The free margin is rounded on the outer part of ray. General 
surface is covered with flattened granules, similar to those of the dorsal marginals, but on the actinal 
surface these are rather more squamiform and subacute. The actinal surface is beset with prominent, 
tapering, occasionally slightly flattened, sharp, mobile spines, about 5 mm. in length, there being 12 
to 20 to each plate. They are smaller and fewer in number on the outer part of the ray. 
Abactinal surface is capable of some expansion. Plates are flat, hexagonal, and regular on 
the radial areas, a papular pore being situated at each angle of the hexagon. The papular area is 
widest in the basal radial area, constricting on the ray and toward center of disk, where there is a 
narrow circular papular area (bounded externally by the madreporic body) surrounding the anus. 
The large triangular interradial area is devoid of papulae, and is paved with mostly 4-sided plates, 
which, like those of the radii, decrease in size as they recede from the center. They are covered with 
crowded, round, flat-topped or only slightly convex granules, larger than those of superomarginals. 
These granules increase in size toward the center of disk, and the centrally situated granules of each 
plate are slightly larger and usually more convex than are those at the sides. The plates of the radial 
papular areas are armed with larger, globular granules, one much enlarged, and often subconical, with 
3 or 4 similar granules nearly as large grouped around it. Along the proximal portion of each papular 
area the plates of the 3 to 6 median longitudinal series bear each an erect, central, conical spine, as 
long or longer than the inferomarginal spines (5 mm.). In the type this spiniferous area is 50 mm. 
long by 15 to 20 wide. There are, besides, 5 stout spines around the anal opening. These abactinal 
spines are very characteristic and are more conspicuous in the medium-sized specimens than in the 
“giants,” such as the type. The radial and either adradial row of spines are the longest and subequal; 
while a varying number of lateral shorter series is added at either side. • Granules are often arranged 
in circles about the base of a' spine, and the enlarged central granule of the other plates of radii is 
graduated in size in such a manner as to become smaller as it recedes from the spines. On the ray 3 
to 6 granules larger than the others replace this central granule. 
