482 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 
preceding series of species. The orbit is small: 3.8 (4.1) in the 
head; 1.75 (1.85) in snout; 1.15 (1.25) in postorbital. The least 
interorbital width is contained 1.4 (1.5) times in the postorbital; 
least suborbital width, 2.2 (2.4) times. The upper jaw (4.5 and 
4.8 in head) extends just a little beyond the vertical from the 
hinder margin of the pupil; the teeth of the premaxillary are 
somewhat enlarged in an outer series. The barbel is short and 
very slender, 6 (5) in the postorbital; 6 branchiostegals; fold of 
gill-membrane very narrow. 
The anus is located immediately before the anal fin, well behind 
the vertical from the origin of the second dorsal. Its distance from 
the base of the outer ventral ray is notably longer than either the 
distance between the ventral and the isthmus or the postorbital 
length of the head, and is contained 2.6 times in the head; the dis- 
tance between the ventral fin and the isthmus is equal to the length 
of the orbit. The anus is preceded by a small scaleless black area, 
from which a black line extends forward to the oval ventral fossa, 
which is covered by very thin, smooth scales, and is located just 
anterior to the ventral fins; the fossa is one-third as long as the 
postorbital; the distance from the center of anus to the front of the 
fossa is half as great as the length of the head. Distance between 
outer ventral ray and isthmus, 1.25 in postorbital. 
Twenty-one pyloric caeca, shorter than the orbit (in paratype). 
The scales are well imbricate and of medium size; 5 (or 54) in 
- a series between the front of the second dorsal base and the lateral 
line (excluding the lateral line scales). Each scale of the body bears 
5 to 7 poorly developed, slightly divergent carinae, which are armed 
with six (or fewer) spinules near the middle of the scale, where 
they are strongest and most numerous; these spinules are sharp and 
slender, and are directed backward; the last ones project beyond 
the margin of the scale. The spinules on the scales of the head are 
in general similar to those of the body, but are strengthened moder- 
ately on the supraorbital, postorbital, and occipital ridges; those on 
the snout and on the infraorbital ridge are characteristically small 
and suberect. The long, sharp dorsoterminal plate is armed by scat- 
tered spinules above, and by a marginal series (the strongest) on 
each side; the ventroterminal plate is armed by five series of spi- 
nules; the bases of the terminal plates are bounded by the ‘first two 
scales of the 9 to 11 which cover the ethmoid region of the infra- 
orbital ridge; the preorbital region of the ridge is covered by 14 to 
17 scales in a single series, while the preopercular and suborbital 
regions, behind the posterior margin of the pupil, are covered by 
a double series; from this double series there extends forward, be- 
tween the scales of the ridge and the eye, a diagnostic row of modi- 
fied scales bearing two strong series of spinules. The median ros- 
