PERISTEDIUM BARBIGER. mlalat 
from which a low keel extends to the orbit, each process with three outlets 
of the lateral system on the lower side anterior to the mouth and a fourth 
opposite the maxillary ; a hooked spine near the inner side of each nostril 
and a sharp spine at each outer edge forward of a slight prominence 
nearly opposite the nostrils. Mouth wide, lower jaws much shorter; max- 
illary extending two thirds of the distance from the bases of the rostral pro- 
longations to the eye. Chin barbels numerous, closely bunched, compara- 
tively long, the groups of the two sides hardly separated below the isthmus, 
outer barbel with about twenty barblets, reaching a vertical from the middle 
of the eye. Eye large, equal in length to the rostral processes, or to the 
width of the interorbital space, one fifth of the entire length of the head, 
prominent. Interorbital space concave transversely, ending at a spine of 
moderate prominence above the hinder edge of each orbit. Back of head 
depressed, slightly concave, with a low ridge at each side on which behind 
the postorbital spine there is a low spine or prominence and another at the 
end on the back of the head. No ridge or prominence behind the orbit on 
the side of the head. A short opercular spine from which a ridge extends 
forward. Subopercular spine hardly longer than the opercular. A very 
low keel starts below the middle of the snout at the edge, and continues 
back toward the ventral fin. Gill openings moderate; lamelle short; 
rakers five plus sixteen, short, clubshaped. Pseudobranchie small. Head- 
shields all granular, an obsolescent spine above the forward part of each eye. 
Scales rough, granular, in four series on each side, wider than long, each 
with a sharp compressed and hooked spine, except on eight or nine of the 
hindmost in the second row from the middle of the back in which the spine 
is compressed into a blade at each end of which there is a cusp the anterior 
being antrorse the posterior retrorse. Abdominal plates enlarged, each 
with a low keel in which there is a spine of more or less prominence. 
Genital papilla medium. 
Fins medium to small; first dorsal rather low, longest ray equal to post- 
orbital length of head; origin of second dorsal midway from end of snout to 
end of caudal, slightly in advance of the origin of the anal; caudal small, 
half as long as the snout, equal in length to first ray of first dorsal, poste- 
rior margin concave ; pectorals broad, one and one fourth times as long as 
the orbit, rounded on the margins, upper of the two free rays the longer; 
ventrals comparatively large, rounded, hindmost ray united to the body by 
membrane for half or more of its length. 
