380 FISHES OF WESTERN SOUTH AMERICA 
writers have not recognized the species as more than a variant of the versatile 
agassizit. I have one specimen, the largest named above, which corresponds 
definitely to the brief synopsis and to the figure of Castelnau, a fine specimen for 
which I take pleasure in reviving the name tschudii. 
Two of the 16095 are of moderately erect form, the largest extremely elevated. 
Taking my description from the largest we find it: 
Much compressed, well-armored in large, close-set scales, regular on the after 
parts, and enlarged, less regular, cornified on the forward parts. Dorsal contour 
straight on head, greatly arched and highest above the pectoral basis, nearly straight 
thence to the caudal peduncle; ventral profile of uniformly slight convexity to the 
anal basis, thence obliquely by the anal basis to the straight caudal peduncle. 
Depth 2.8-3.5; width moderate, 1.4-1.7 in the depth, 1.8-1.4 in the length 
of the head; caudal peduncle deep, exceeding considerably the length of the post- 
orbital head region. Head rather large, 3.3-3.5 in the length; eye well in advance 
of the center of the head, elevated, large, slightly elongated, its bony orbit promi- 
nent, equal to snout, 4.5-5.0 in the length of the head, 1.8 in the interorbital space; 
snout angular, pointed roundly in profile; mouth narrow, cleft deeply below orbit, 
horseshoe-shaped in front aspect, thin-lipped, with a series of unusually prominent 
teeth; cheeks not at all swollen. 
Scales nowhere conspicuously striate, becoming thickened, cornified, irregular 
on head and 6-7 scale-rows on and about the lateral line beyond the opercle; 
investiture complete. Few scattered scales on the infraorbital space; cheek to 
beyond the eye, and the opercle, except its anterior horn, heavily scaled; pre- 
pectoral only lightly and incompletely so; preventral broadly, and postventral 
narrowly scaleless; vertebral series 13-15, three series regular. Smaller specimens 
more miiller-like, more deciduous. 
D. 13-15; A. 13-15; P. 17. 
Fins of exceptionally large size, longer than deep, not rounded as in most 
species; dorsal basis, beginning at midway-point of the trunk, exceeds its distance 
from the first caudal ray; pectoral more rounded, and reaching beyond the midway- 
point to the anal origin. 
Alcoholic specimens still show an olivaceous color, especially on the bucklers, 
shading into yellow-green, and then yellow on the opercle, and to brown on the 
back, brown on the scale-margins of the sides and after-parts. Many scales of the 
dorso-lateral area with lighter centers, bordered with dark. Fins darkened between 
radu, especially near the bases; no spotting of fins except, slightly, the pectoral. 
The smallest of the three best specimens differs from the other two in the much 
more rounded back, more pointed snout, fewer teeth, fleshy lips, and smaller, 
more circular eye. The largest is notable: 
In the size and position of the eye, form of the mouth, scalation, fin-charac- 
ters, colors, there is much resemblance to jussie/; differing from the latter in the 
greater compression, more moderate width at the shoulder, deeper, shorter caudal 
peduncle, and in the largest specimen, the abrupt angle in the dorsal contour 
above the base of the pectoral fin. 
