CARBONIFEROUS FISH-FAUNA, 
front; while not uncommonly they are inconspicuous on the 
middle of the scale, which then becomes smooth (Pl. IX, fig. 14; 
Pl. X, figs. le, ld, le, 1f). The direction of the ornamental 
ridges is least oblique and most regular on the principal abdom- 
inal flank-scales (Pl. IX, fig. 1b; Pl. X, figs. le, 1f); much 
more oblique or ever diagonal on the principal caudal scales (PI. 
X, figs. le, 1d, 2a, 2c). The characteristic arrangement on the 
ventral scales is indicated in Pl. X, fig. 2b. The narrow, 
diamond-shaped, small scales of the upper caudal lobe are 
ornamented by fine, diagonal ridges, as shown by impressions in 
the type-specimen and in the original of Pl. IX, fig. la. The 
enlarged ridge-scales are not seen in the type-specimen, but 
some of those in advance of the anal fin are shown in the original 
of PIX, fig: 2. 
Remarks.—The impression of an imperfect, relatively large 
trunk represented in Pl. X, fig. 2, is not referable to this species 
with certainty; but the shape and ornamentation of the scales 
seem to agree precisely with those of the fish now described. 
This and the type-specimen were found by Mr. George Sweet, in 
whose honour the species is named. 
ELONICHTHYS GIBBUS, sp. nov. Plate IX, fig. 4; Plate XI. 
Type.—Imperfect fish, lacking end of tail (Pl. XT, fig. 1). 
Specific characters.—A short, deep-bodied species with com- 
paratively small head, attaining a length of about 0.2 m. Length 
of head with opercular apparatus somewhat less than the maxi- 
mum depth of the trunk, which is contained twice in the length 
from the pectoral arch to the base of the caudal fin. Pelvic fins 
arising about midway between the pectorals and the anal; dorsal 
and anal fins at least as long as deep, the former not completely 
in advance of the latter. Principal seales of flank in abdominal 
region slightly deeper than broad; outer face of all the scales 
completely ornamented with fine, somewhat oblique ridges, which 
terminate in the delicate serrations of the posterior border. 
Enlarged dorsal ridge-scales apparently extending as far forwards 
as the occiput. 
[22] 
