623 Mr. C. T. Regan on 
teeth, those of the outer series of the upper jaw enlarged; no 
canines. Posterior border of preoperculum dentated, the 
angle with two fairly strong spines, the lower pointing down- 
wards. Gill-rakers equal in length to 4 the diameter of eye, 
16 on the lower part of the anterior arch. D. X, I 28, the 
third and fourth spines the longest, equal to 3 the length of 
head. A.II 8, originating below the thirteenth branched 
ray of the dorsal, the second spine stout, equal to 4 the length 
of head. Pectoral pointed, equal to # the length of head. 
Ventral spine equal to $ the length of pectoral, the outer 
branched ray with a short terminal filament, extending nearly 
as far back as the pectoral. Caudal doubly truncate. Scales 
finely ciliated, arranged in vertical series both above and 
below the lateral line, 55 in a longitudinal series, 6 between 
the base of the first dorsal spine and the lateral line. Depth 
of caudal peduncle 22 times in the distance from the base of 
the last anal ray to the caudal. Olivaceous above, silvery on 
the sides and below; upper half of the body with brownish 
stripes, which posteriorly run horizontally along the middle 
of each series of scales and anteriorly curve downwards and 
run vertically. Membrane of the fins dusky. 
Total length 250 mm. : 
A single specimen, obtained at Montevideo by Mr. M. J. 
Nicoll during the voyage of the ‘ Valhalla,’ and presented to 
the British Museum by Lord Crawford. 
Acara sapayensis. 
Depth of body 22 times in the total length, length of head 
25 times. Diameter of eye 3} times in the length of head, 
interorbital width 22 times, length of snout 2% times. Max- 
illary extending to the vertical from the anterior margin of 
eye; breadth of preeorbital equal to % the diameter of eye; 
cheek with 3 series of scales; 5 gill-rakers on the lower part 
of the anterior arch. Sc. 26 %. LL. lat. 15-17+8-9. 
D. XV 10, the spines increasing in length to the last, which 
is equal to # the length of head; the soft tin pointed, the fourth 
and fifth rays longest, extending to beyond the middle of 
caudal. A. III 8, the first spine half the length of the 
second, the second ? the length of the third, which is equal 
to 2 the length of head. Pectorals and ventrals extending 
to the level of the origin of anal. Caudal truncate rounded. 
Length of caudal peduncle 14 times in its depth. Dark 
brown, with 6 obscure blackish cross-bands on the upper 
half of the body ; some small blue spots on the head; fins 
blackish. 
